I recently stumbled across this deleted answer (10k+ users only). It seems like a good enough answer to the question it was posted on, with a fair amount of detail, but was deleted by a moderator as rude/abusive purely for its opening remark:
You really need to work on your writing style. This sounds like the most arrogant question of all times.
This sort of remark has no place on Stack Exchange: it's unfriendly and unnecessary. Had I seen this answer prior to its deletion, I would have edited it out, and probably left a comment politely asking the user to refrain from making such remarks in the future. But I wouldn't have deleted the entire answer, because the rest of it was fine (albeit in need of some SPaG edits); it was just that one bit that needed removing.
My first thought was that the mod was being too harsh in deleting the answer entirely, instead of just removing the offending statement, but it's also possible that my approach is too lenient. So I thought it best to ask what the best practice is, especially since I'm currently running for pro-tem mod on another SE site.
If an answer contains a single rude/abusive remark but is otherwise a perfectly valid answer, is it acceptable to just remove the offending statement? Or should the whole thing be flagged as rude/abusive and deleted?