Any kind of direct response to a post that ought to be excised (and there are such posts) makes it harder to excise it, because, unless the response(s) are removed as well, it'll be hard to make sense of the thread. And the better and more interesting the response, the worse. Otherwise you end up with the original post permanently preserved, as has happened in this thread.

If there has been a personal attack on us, or more relevantly, on someone else (as with a couple cited in this thread), it is possible to write a post that sets out to set the record straight but which makes no direct mention of the offending post; it can be written in such a way that it will still make sense, if that post is no longer there. That seems to me a much better way of going about it.