Pretty simple, 4v4 RT has a lot of level 1 bots that simply afk and/or leave at the start of a game. Many have names like ‘afkbot90’. If a blizzard mod could simply disable the cdkeys of some of the abusers, they’d be small enough in number to stamp it out entirely. They’ll run out of cdkeys quickly. From what I can see on azeroth there’s only a handful of them, but they flood the queue so most games have 1+ of them, ruining it.
They aren’t even set up to abuse 4v4 to win by matching a specific human player and leaving to imbalance the teams- they’re just trying to ruin the game for everyone.
If any blizzard classic games team is actually interested in stopping them and need help identifying the obvious abusers- not just people who have done it once or twice or made someone mad at them, but the 0-100 botted accounts- it would be pretty easy to get some people in the community to point them out.