Wealthy students (or their parents) pay full price, supporting the university and all it's operations. Many of them pay more than full price via donations and such. One of the things they are paying for is support/scholarships/etc for the poorer students.

I don't think a grad student's stipend is a handout, just as I don't think my salary is. Nevertheless, grad students should be grateful to the undergrads/taxpayers who are supporting them, and I should be grateful to my employer's customers (I am).