I think people can explain away the Avengers and their powers. Aliens, gods, trillionaires. Got nothing to do with me.
But if Jim Bob’s next door neighbor DeMarcus can all of a sudden fly, or Jim Bob Jr. ends up in the hospital cause Xiao electroducted him at school he might not like them as much as he likes Iron Man. Also, never underestimate the ability for a person to carve out exceptions or rationalize their bigotry.
If the X-Men shyt flops it will be because they did a bad job not because why would people like the Avengers but hate mutants.