The problem with Brain-Thinking - the mind as brain as information-processor, is not that it is utterly false. It is not false - it describes well many aspects of thinking.
The problem is that, firstly, it is merely a model - hence a partial truth: necessarily incomplete and distorted; and, secondly, that Brain-Thinking has captured belief in public discourse to such an extent that other understandings of thinking are assumed to be, not merely false: but impossible. Thirdly, following-on from monopolisation of public discourse - the assumption has invaded and colonised the mind itself.
Because people have come to assume (assume, mostly without thinking) that Brain-Thinking is the only possible model of thinking; Brain-Thinking has become a self-fulfilling assumption. Any thinking which does not fit the model of the mind as a biological-computer is regarded as childishly-mistaken or actively-delusional.
Since people do not wish to regard themselves as dumb or deluded; this has, over time, meant that our culture has restricted first its communications about thinking, then later (and increasingly) actual thinking itself, to a form which fits within the Brain-Thinking model.
In other words, actual thinking is now (mostly) restricted to automatic and externally-determined processing of information derived from sensory inputs (or from memories of sensory inputs). Actual thinking has become passive. People regard themselves as functioning like computers, driven by inputs in accordance with their processing software.
The possibilities of human change are increasingly seen in a transhumanist frame; where improvements to Men are conceptualised in terms of re-programming, or being enhanced by upgrades.
It seems quite natural to younger generations that the essence of a person could - in principle, and 'soon', they assume, in practice - be down-loaded from the biological-computer of the human brain into a silicon computer; or even translated to pure information, encoded in whatever convenient form is available (binary code stored in a hard drive, or captured in a single complex artifact).
This is, indeed, a standard current trope of 'immortality' - that our-selves might live forever in the 'purest' essence of a characteristic pattern of information-processing.
Other types of thinking, especially Primary Thinking (for example genuine creativity or intuition, direct knowing, telepathic phenomena etc.) is either re-conceptualised into forms of information processing (which abolishes even the possibility of real creativity, intuition, direct knowing, 'telepathy'), or else they are rejected outright as naive or exploitative obsolete formulations - now superseded...
That Brain-Thinking is the only possible thinking has therefore passed swiftly from being an assumption - and an assumption which would be impossible to prove; into being treated as a fact: a fact-supported-by-overwhelming-evidence.
In other words, the exclusive truth of Brain-Thinking is (like the theory of evolution by natural selection) an example of metaphysics masquerading as a scientific discovery. As such, it is tyrannical - because a metaphysical assumption can never be disproved by any observation or experiment - since all possible (all evidentially-allowable) observations and experiments are interpreted within the metaphysical framework.
Consequently, many modern people are trapped by their assumptions into inhabiting a world of experience framed exclusively by Brain-Thinking - a wholly-determined world, with no possibility of freedom; a world which excludes the possibility of any reality beyond the five senses.
And - given inevitable imperfections and errors in bio-processing and memory; this is also a 'relativistic' world in which we can never be sure of anything.
In other words, an inescapable nightmare world; and a mind-set that makes it possible (for the first time in history) for rulers really to manipulate the thinking of everybody, forever.
(My echo of Orwell's phrase from 1984 is deliberate.)