If it was possible to write an effective slur filter, I would not find it completely objectionable. Not because that would be useful to stop people saying completely shit-headed things if they really wanted to (I strongly suspect you could get the entirety of Mein Kampf past that filter), but as a "people who use these words are not welcome" signal, which definitely has some value.
As it is, it's bashing the problem with regular expressions, and doing so badly. I mean, some of those words actually have completely different, non-offensive meanings in certain communities & contexts. (One of a few I spotted: Last time I used "retard" was in the context of ignition timing...)