Calling it all racism is a thought-terminating cliche. Not all groups of humans have the same societal values, and that is not intrinsically tied to race. It is economic in origin. There certainly are racists like you describe, but they are most likely a vocal minority.

The wealthier a society becomes, the more picky it can afford to become. Personal autonomy can be selected for easier when hand to mouth subsistence isn't taking up 100% of your time. Things like Abrahamic religious laws arise from subsistence societies. This doesn't make cultural friction any less real or impactful.

Women's rights and abolition of child marriage is the result of privilege, but that doesn't mean they are bad things. When "most" people talk about integration, they are broadly talking about adoption of those values.

To your final point, sadly a mass reduction in habitable land will almost inevitably result in reciprocal population loss. Probably violently through wars of conquest for the remaining resources.