Obscenity have always bothered me, because of their capacity to do more damage than they prevent. I understand why they're there, but between these kinds of minor gaffs, and... well, let me tell you about Maple Story. Maple Story used to chop all the spaces out of your chat strings and filter the entire message if it found anything distasteful. It doesn't sound bad, but it was trigger happy. If you type out entire, complete sentences, you run into the filter all the time. So, Maple Story selected for people that chatted in short, sloppy strings, a consequence that I find dissatisfying.
MGS4 is a "mature"-rated game, too. Then again, it is the larger Konami ID network, and I guess they have grandiose hopes for it or something. In case you're wondering, my solution is to use a fall-back name. Masterbull solutes you!