That's true. You can more easily be accused of obfuscating or pulling something out of context if you don't quote the entire exchange. Like in this post, sometimes I don't quote the prior exchange at all, since right now there are only a few people in the thread thus far.
So, StetsTerhune, at what point are you going to bow out of your own thread? ;) I have to admit there is only once that I have done that in a thread I started myself, and that was because I was just done. I had gotten the advice I needed, the situation in my real life was over anyway, and someone was annoying me. So I said my thank yous to everyone who helped and haven't commented again. Once every few weeks, the "debate" over my original post continues and I just think, "Oh, no, not THAT again." But I don't think it's useful for the OP to lock a thread, even though I understand why some people do.
This is somewhat related - I have found comment sections of major newspaper articles to be unreadable -- not only because many of the commenters are just not that intelligent and clearly don't know how to argue -- but also because people get into these side arguments that have nothing to do with the article. Sometimes I have to scroll through 100s of replies to even get to the next comment. Slate comes to mind. It's maddening. I know comments can't necessarily be moderated but too many people are commenting these days with dumb banter to even make it worth my while.