"offensive" isn't the only reason for downvoting. "Not a substantive addition to the conversation" is one (of many) other bases. If you are going to complain about downvoting [1] why do so based on the unwarranted assumption that the downmod must be for offensiveness?
[1] And you shouldn't, see the Guidelines [2] under "In Comments"
In my opinion, if HN doesn't want puzzled people to ask why they've been downmodded, then instead of putting a line in the Guidelines saying "don't do this", they should separate the downmod into "I disagree" and "flag this as a bad comment", with the latter item the one that reduces the text weight. It's clearly broken - people have been doing this for as long as I've been here, and it's not going to change (sadly, 'it' means both the behaviour, and HN's braindead downmod mechanism).
