There’s some dog whistley aspects for sure, but I think a lot of it boils down to just plain ignorance about institutional problems.
MAGAs think you can just decide not to be poor and if you work hard enough you can be rich. So when MAGAs struggle themselves to make a comfortable living, they can only make sense of it by blaming someone else for conspiring against their happiness like the president, immigrants, other people getting any kind of help, etc.