Now, is it just me, or this a pathetic concession to the dramahounds? Someone makes a post, gets a few nasty comments to it (perhaps quite justified), and gets whiny about it. They get in the last word and freeze the comments, thereby feeling superior and driving everyone else crazy, who are now not able to get their own two cents worth in, starting a roving flamewar. Or maybe some troll, bouncing around a community, making posts that are just begging for controversy and then freezing the comments...you know those people are out there; Hell, I could name you a few.
I guess I just don't see the use in this, other than as a further annoyance that feeds all those jackasses on the Internet who like it because they can get away with saying something they'd never have the balls to say in real life. Now, sure, i can see how it could be useful to stop a running flamewar in your post, between others...but making something this universal for a small problem like that is like nuking the planet to get rid of the bugs.
If you can't hold your own in the convo, then shut the Hell up. If you personally are just getting the comments by mail, and you aren't even involved anymore, turn off e-mailed comments for that post, and let the buggers yell it out between themselves. Chopping off the communication by 'freezing' things only serves to make the combatants mad at you.
But then, humanity is all about dumb stuff, eh?