Racism, and misogyny appear to be the deeper issues vs the more general and generous stupidity.
I put it - as an outside chance - that it is possible that the policies and outcomes of said policies have a bearing on the voting decisions people make.
Seems a bit of an overclaim. Strategic questions of how to handle the border was a defining issue in the 2016, 2020 and 2024 elections. Americans are continuously voting on border policy, it is one of the major elements of their national conversation. What the Biden administration did was a bit extreme but ballpark what was on the tin when he was voted in.