On Stackoverflow with it's higher visibility and factual natural, this might not come across often, but on stack exchange for say "interpersonal skills", a lot of non-factual opinions are expressed, so that can cause moderator bias.
For example if you don't like someone's wording on something or believe in certain things, you can remove all opposing comments when they are completely legit. For example, this issue. Mutiple people pointed out that the correct top two answer aren't useful. It might sound nice to "simply to truthful and respectful and ask", but that's not what the OP is asking and he clearly mentions it (that he doesn't want to risk offending the other person). Even the question is posted as "how to check" not "how to politely ask". All such comments were deleted for some random reason... Why?