Is poltical correctness doing more harm then good?

It seems to be that people (mainly whites) seem afraid to ask others questions based on ethnic, religous, or orientation without feeling that they'd offend. Terms like for example Black American are used 24/7 regarding blacks, even if they're not american. I think those people think the world Black sounds offensive? But anywho do you think Poltic Correctness is actually helping stereotypes stay by making people think safe thoughts and not actually thinking? For example if I asked a question like Why blacks and latinos are doing poorly in schools overall I'd get answers like "Not all blacks and latinos are doing poorly" Instead of "Because of family and economic problems, etc..."