I'm glad that has been brought up. Insults do not imply negative sentiment words (nor do negative sentiment words imply an insult).
In addition to the joke put-downs you gave, there is also sarcasm ("Yeah, sure, I want to go out with a find-upstanding member of the community like you."), but another class of insults can use all positive words and no sarcasm:
I'm sure you will make a fine Mc.Donalds crew member.
This could be insulting their ambition, or their academic prowess. But, instead, it could be said by a proud parent to a teenager upon getting their first part-time job. It could simply be a complement on the person's ability to work in a team. In the hands of certain parents it might even be all three at once.