I rematch with people all the time. I literally rematched with someone in my last game just a second ago playing 10/0. Are you the sort who refuses to resign even when you have a hopeless material disadvantage?
I have won a couple games after being down with a seemingly hopeless material disadvantage. I'm not a grandmaster, and they don't play me (I suppose they might to laugh at a bad player, but that is unlikely). Until you get to the very high levels you should not assume your opponent knows how to convert even an easy endgame.
> It is good etiquette to request a resignation in chat?
Not a chance. People at lower ratings screw up what should be wins all the time. Your opponent may be hoping for a stalemate or to run out the clock or waiting for you to blunder.