On the one hand, yes, words shouldn't be hurtful, they are only as powerful as you let them be an all. Which is fine in theory.
But, c'mon, everyone gets hurt or offended by words to some extent every so often. Sure, they only have the power we given them, but we've given them an awful lot of power. Racist/sexist slurs are there for the purpose of hurting people, in the pervasive belief that they are less than.
Sure, in an enlightened society free of prejudice, such words would presumably lose their power. But the thread is likely to come to an end before we reach that point.