I'm confused where I ever stated that it wouldn't be toxic? Can you point that out? The situation you describe would be toxic no matter what. It is not only toxic because there is a timer for M+. Blizzard is not responsible for that player leaving, are they?
Doesn't this just prove my point? That people will choose to be toxic unless forced not to. So the responsibility is on the person making the choice and not on the person that didn't force them. It really isn't surprising that people shift blame for toxic behavior from themselves to developers. It is a convenient justification for any action they take and allows them to stoke rage at the developers for no good reason.Like what do you gain by being nice now?