You're making the mistake of thinking the human brain has an infinite capacity to expand its intuitive empathy. It just doesn't. No more than your bixepf has an infinite capacity to increase it's strength. You can fulfil that potential more or less but you'll still never win an arm wrestling match with a gorilla or a robot. Humans have finite limits to their potential. Our current society and most of the proposed alternatives is structured in such a way as to only really work if humans generally have a far higher capacity for intuitive empathy than humans have.

That is fundamentally a flaw that must be overcome by a more thoughtful and purposeful design process than either "well this is just kinda how things ended up really" or "let's imagine if things were different, but not too different because that's hard!" (because our brains are also kinda bad at imagining things being seriously different to how they are.) Or if we decide for actual specific reasons that it isn't viable to even attempt to approach a human society that is shaped to humans rather than one which humans have to clumsily try to shape themselves to, we have to find ways to overcome the limitations of our biology. Often we do a good job of that externally, but for this it might only be possible through trans-humanist approaches. Which to be seems like it should be something we consider because we must, not because we think it is somehow more convenient than thinking purposefully about how we should share our lives together (though for the purposes of that, we may also be currently limited by how well our languages allow for those discussions to meaningfully occur. That's a fairly solvable issue as we are constantly evolving new ways for our languages to help us express ideas they previously didn't easily cover.)

As for the difference between the mind and the brain I'm not convinced by your argument at all. The mind is an emergent property of the brain but that does not make them one and the same any more than it makes Windows 98 an x86 PC.