This for me mostly. A few times i've come across players like that and i'll just drop the controller and let them have their practice mode dummy. No point in trying to do anything when i've literally got 0% chance at getting a hit in let alone winning a round. But other times i'll quit just because i can't be stuffed waiting for the guaranteed loss.
And i don't see what the big deal is. As far as i'm aware, if you quit (not disconnect), the other player still gets his finisher (if it's not before the end of the game), they still get their points and they still get the win. So whats the problem?
Yep. You quit at Finish Him, you don't have to wait 5sec + fatality + win pose + currency count. It's a small amount of time, but it does add up over time. People might say it's because they're salty, and there is that to some degree, but just getting to the next match as quickly as possible is what it's about.
And then there's this... which is also true.