I'm never sure how angry to get about these kind of things, because on the one hand I'm pretty sure that Amazon sells a lot of stuff that they themselves consider offensive, at least to an extent. Nonetheless, I think this crosses the line into the territory of stuff they just shouldn't be selling: Bumper stickers that say "My Catholic Priest is Dating Your Son". (Do a search for "Catholic" under the automotive catagory and it's the top thing you get.)
Now, to be fair, Amazon is not the actual seller for these items, it's one of their vendors BumperArt. So it's possible that Amazon doesn't actually know BumperArt put these up. If that's the case, it would seem that it's time for them to find out and do something about it.