Answer:
Maybe because America is built on the idea of "living the American dream" which is centered around struggle, so when people tell someone who is rich and is in a privileged position they immediately assume the person is calling them a freeloader who didnt earn anything. They dont like to stop and think that just because you earned it doesnt mean youre not privileged and this is stemmed from ignorance towards people who are disadvantaged. Sometimes that is the case where people are generationally wealthy, meaning they are privileged because they were born into it and they cannot fathom the idea that they didn't "live the American dream" through struggle since they never had to struggle in their whole life.