If u have to jump out and deal with irl stuff fine, u can wait out a time penalty while u are gone anyways. Wont affect them, but ppl leave all the time when losing, which ruins the game for everyone else, and then the poor person who wasted their queue on a backfill game. Often near the end of the game too.
Exp penalty and losing endorsements after leaving a bunch is hardly a penalty people care about. Not going to stop them from quitting and ruining it for everyone else.