I am with the OP, Blizzard does not punish AFK/leavers. I can kinda prove that too.
Wrote this thread a little over a month back about how Gall, as a bot, is a LOT better than most players. Thing is, in order to make Gall a bot, the player (my 2nd account) has to leave the game…
To put this in perspective, that 2nd account has technically been afk/left OVER 100 CONSECUTIVE GAMES. And there has been no action from Blizzard. NONE at all.