Why do people go offline in M+?

Again, people leaving keys on a normal basis was nothing Blizzard addressed.

Let’s go ahead and properly quote relevant segments here.

So no. This isn’t a “Payne left a couple of keys this week, time for some account action” situation. They targeted people deliberately leaving keys to an excessive degree, some of which were (per their own words) “deliberately intending to harm others’ experiences”.

If you’re going to quote the blue post, at least quote enough of it for a clear picture. Then again, you seem interested in engaging in fearmongering, so I’m not sure if you’re even going to listen to what I say to you.