There's no reason to ever demand a resignation. Your opponent has every right to use all the time they've been given (just as you do).
If you're winning, simply checkmate your opponent. If you're unable to do that, it's your own fault.
If you're mad that your opponent is taking too long by playing on, then you shouldn't have chosen to play a long game, in the first place. That was your choice to play at that specific time control - not your opponent's.
Demanding a resignation (which, to be clear, has never happened to me) would make me want to extend a game as long as possible. I'll resign when I think I've exhausted reasonable outs. But sometimes I'll play on in long shots because people make mistakes, and also there are sometimes learning opportunities.
I do think it's funny when people get aggressive in chat with taunts only to find themselves forked, losing a major piece, and on their way to getting mated. I live for those moments.