The brain exists in a physical universe, made out of matter/energy, and its behaviours are entirely dictated by the laws of physics; that's a fairly accepted truth unless you have solid evidence otherwise.
The laws of physics are mathematical and can be computed by their very nature, and we are already pretty good at simulating physical interactions to a quantum level, and this ability improves over time.
At some point in time, unless there is "magic" or missing physics, a sufficiently powerful computer with a physically accurate simulation of a brain would produce virtually identical results to a real brain.
So either there must be new physics involved, or, the notion that a sufficiently advanced computer simulation can't produce imagination must be abandoned.
A team of scientists able to sufficiently model the physics of the brain (and presumably the entire central nervous system, I imagine a disembodied brain simulation would experience a horrific form of locked-in syndrome) would not need to be concerned about emergent properties of the simulation such as a sense of consciousness, or thought, or imagination. Those things will just happen once the simulation is perfected.
Indeed the cognitive neuroscience folk, etc, would be invaluable to actually understanding, training, interpreting and caring for the brain simulation, and figuring out if its behaviours and interactions constitute consciousness etc, so I do not think this has to even be framed as programmers pretending to know about brain stuff vs brain people who dismiss any notion of computationally recreating consciousness. It would be a team effort that works both ways, but is already doomed to fail if half the team thinks it's impossible from the get-go.