If you are certain to lose anyway, why waste time? Not all players have plenty of time to spare so it would be wise to quit a losing game and quickly move on to the next. That's called being smart in saving time.
Oh please, rage quitting in PvP was around long before Fur Hire. I can't even count the number of people who have rage quit the moment I have the advantage. Hell I'm guilty of it once or twice myself but I would rather get the EXP so if I'm out of options I'll just leave my field empty.