The impersonalist yogis, materialist, scientists, scholars and devotees reject Kṛṣṇa being an "eternal individual Person" as a spiritual bodily Form who is the Supreme Personality of Godhead and cause of all causes.

Most impersonalist have the incorrect knowledge that wrongly tells them, the life force in the material bodily vessel (known as the jiva-souls who are eternal individual units of indestructible anti-matter), once free from a material bodily vessel, merges back into the "oneness of an all-pervasive life force or universal consciousness," 

Just like when air is released from a container and becomes "one" with the air around it, or when water is released from a container, merges back into a "oneness" of an ocean of water.

They do not accept the fact that the "life force," or individual units of living spiritual energy (anti-matter), is a collection of unlimited individual jiva-souls existing as active eternal spiritual bodily forms in their full potencial in the spiritual world, headed by Krsna, the Supreme individual Person (God) who is the cause of all causes. 

The impersonalist do not accept Kṛṣṇa, Visnu, Siva or their representatives, they eventually only seek one desire after becoming fed up existing, to end all activity and cease to exist by attempting to permanently enter the impersonal inactive bodiless brahmajyoti and never fall out of the "inactive impersonal dormant brahmajyoti" which is attempted spiritual death or voluntary suicide.

They know that presently their impersonal beliefs allow them to enter the impersonal brahmajyoti, where they can remain there for trillions of life times of Lord Brahma.  

However, eventually they MUST again fall down from their and take birth in the material world, because the eternal original nature of the individual jiva-souls, is they are always "active" in their natural eternal constitutional original spiritual position in Krsna's service, as an eternal spiritual bodily form in Goloka Vrindavana (Krsna's Abode) or in the Vaikuntha planets (Visnu/Narayana's Abode) in the spiritual world.

Or can, if they choose, continue trying to enjoy separate from Krsna in their unnatural position "active" in the material world, covered by a temporary material bodily container or vessel [form] 

There are 8 million 400 thousand species of material life (bodily forms) the fallen individual jiva-soul can enter.

The impersonalist do not want to be "active" in either the spiritual or material worlds, they prefer not to exist at all by extinguishing their individual existence, denying the existence of God and their own unique personality, and instead being under the illusion by entering the impersonal brahmajyoti,  they have become "one" with everything, which is ignorance,impersonalism.

However, this illusion of becoming one with God, is NOT possible, because "anti-matter," who the individual jiva-souls are eternally, is not all-pervasive from the individual jiva-soul's stand point.

Although the individual jiva-souls (individual units of anti-matter) can remain "bodiless" as an individual spiritual inactive spark for trillions of life times of Lord Brahma dormant in the impersonal brahmajyoti.

Whether the jiva-souls are active as their spiritual bodily form, or inactive as a spiritual spark in the impersonal brahmajyoti,  they ALWAYS remain individual units of anti-matter.  

Even over the vast time span of multiple Brahma's life times (each Brahma lives for 311 trillion and 40 billion human years), in the face of Krsna's wonderful creation, is only a blink of an eye. 

Eventually those deluded individual jiva-souls dormant in the impersonal brahmajyoti, again re-emerges from its inactive slumber state and again becomes "active" by taking birth in the material world. 

Those impersonalist who have rejected Krsna and Viṣṇu and want nothing do do with the Vaikuntha planets of Visnu/Narayana, or Krsna's central Abode of Goloka-Vrindavana, attempt to seek out a permanent end (spiritual suicide) to their existence because all their experiences in the temporary material world (matter) always ends in pain and suffering.

However, the individual jiva-souls attempts to permanently end their individual spiritual existence is never possible because they are indestructible. 

Bhagavad Gita As It Is - "That which pervades the entire body you should know to be indestructible. No one is able to destroy that imperishable soul." (BG, Ch 2 text 17)

Although, the fallen individual jiva-souls can reside in the impersonal brahmajyoti for a very, very, very long time as explained above however, as also explained, they can NEVER remain there eternally. 

In other words, the impersonalists want their identity and personality permanently extinguished, but that is not possibe. 

In fact not even Kṛṣṇa, Visnu or Siva can grant this foolish attempted spiritual suicide by the fallen individual jiva-souls because, as said above, the eternal nature of the individual jiva-souls in their original position, is to be eternally fully "active" in Krsna or Visnu's pastimes.

Srila Prabhupāda - "Existence in the impersonal brahman (being inactive and identity extinguished) is also within the category of non-Krsna consciousness and is also only a temporary condition (because the nature of the soul is to be always active in Krsna's pastimes.) Those who are in the brahman effulgence are also in a fallen condition, so there is no question of falling down from a fallen condition. When fall takes place, it means falling down from the non-fallen condition (Goloka-Vrindavana and Vaikuntha). The non-fallen condition is Krsna consciousness." (Letter to Revatinandana dasa, LA 13 June, 1970 and 1971 London)

Srila Prabhupada – "There are no new souls, new and old are due to this material body, but the jiva-soul is never born and never dies, so if there is no birth, how can there be new souls?" (Letter to Jagadisa dasa, 9 July 1970)

Srila Prabhupada - "God is also an individual person eternally as you are individual person eternally, I am individual person, but the difference between God and you and me is this, that you know your business, I know my business, but God knows everyone's business. That is the difference." (Lecture Melb, Australia April 3, 1972)

Bhagavad Gita As It Is - "Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be." (BG, Ch 2 Text 12)

Bhagavad Gita As It Is - "As the embodied soul continuously passes, in this body, from boyhood to youth to old age, the soul similarly passes into another body at death. A sober person is not bewildered by such a change." (BG, Ch 2 text 13)

Bhagavad Gita As It Is - "O son of Kuntī, the nonpermanent appearance of happiness and distress, and their disappearance in due course, are like the appearance and disappearance of winter and summer seasons. They arise from sense perception, O scion of Bharata, and one must learn to tolerate them without being disturbed."(BG, Ch 2 text 14)

Bhagavad Gita As It Is - "O best among men [Arjuna], the person who is not disturbed by happiness and distress and is steady in both is certainly eligible for liberation." (BG, Ch 2 text 15)

Bhagavad Gita As It Is - "Those who are seers of the truth have concluded that of the nonexistent [the material body] there is no endurance and of the eternal [the soul] there is no change. This they have concluded by studying the nature of both." (BG, Ch 2 text 16)

Bhagavad Gita As It Is - "That which pervades the entire body you should know to be indestructible. No one is able to destroy that imperishable individual soul." (BG, Ch 2 text 17)

Bhagavad Gita As It Is - "The material body of the indestructible, immeasurable and eternal living entity is sure to come to an end; therefore, fight, O descendant of Bharata." (BG, Ch 2 text 18)

Bhagavad Gita As It Is - "Neither he who thinks the living entity the slayer nor he who thinks it slain is in knowledge, for the self slays not nor is slain." (BG, Ch 2 text 19)

Bhagavad Gita As It Is - "For the soul there is neither birth nor death at any time. He has not come into being, does not come into being, and will not come into being. He is unborn, eternal, ever-existing and primeval. He is not slain when the body is slain." (BG, Ch 2 text 20 "corrected" 1983 edition)

Bhagavad Gita As It Is - "O Pārtha, how can a person who knows that the soul is indestructible, eternal, unborn and immutable kill anyone or cause anyone to kill?" (BG, Ch 2 text 21)

Bhagavad Gita As It Is - "As a person puts on new garments, giving up old ones, the soul similarly accepts new material bodies, giving up the old and useless ones." (BG, Ch 2 text 22)*^^*