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I feel mean for being snarky on this thread last night. It always seems to me that MNHQ does a pretty good job with regard both to deletes and refusal-to-deletes. There has to be a chunk of discretion left to them -- you can only codify rules up to a point, and the catch-all "not in the spirit of the site" seems like a good cover for just letting the staff use common sense, which they seem to do pretty well.
It isn't hard to avoid being deleted. I don't think I've ever pulled any punches, but I've never been deleted afaik.
When I say I haven't pulled punches, I don't mean that I am a tough speak-as-I-see-it person (yuk and double- yuk), I just mean that I haven't ever felt that the deletion policy gets in the way of saying what I want to say (apart from having to bite tongue in the face of trolls, but that seems a sensible prohibition).