The FT software is set up to obscure "naughty" words already. I don't think it's necessary, but I also don't mind it. Words are altered in a way that doesn't affect meaning and that alteration is done immediately.

So why is it necessary for certain moderators to run about and alter postings?

In this post I used the phrase "bugger all". Look it up on Onelook or some other dictionary. It's slang, but most don't even mark it as vulgar. The FT software doesn't edit it. Yet a moderator went and altered my post to remove that phrase. What's worse, in my opinion, is that he didn't even bother to tell me that he'd done it.