There really is no excuse to rage quit. You joined the match with the full intention of playing through, but if things don't go your way you leave? Ruining other people's fun?
People like that need to be slapped.
this bit is an assumption of yours.
So... People join just so they can rage quit? Wow. That's even dumber than joining and leaving because you're getting stomped.
Then you go to the other end of the spectrum and make a sweeping generalization. Go figure. Since I must be specific. You are assuming that he personally had the intention of staying the match. I said nothing about people in general but by all means generalize if it bolsters your point.