Right, not exactly like this, they had a different word order in their body. People getting banned because they quit is because they have sore people on their teams or opponents who typically report them for other offenses.
Quitting a game is not a bannable offense.
Your complaint can be analogous to running a marathon (26 kilos) in which you aren't completely prepared for and, besides for the feeling of completion, in which there is no reason to complete it if someone wins 30 minutes before you, so once the first 100 people finish, you give up. And, upon giving up, because the winner didn't get to "beat you because you quit," your legs get shot off.
Makes sense.