> something seems to have seriously murdered the subreddit

That’s one potential interpretation. But from observing it closely, it’s probably more of suicide than a homicide.

The show opted to terminate viewer feeds. Subreddit engagement actually increased when that was announced, as fans protested.

But right when the season began, a moderator arbitrarily started suppressing that protest, attacking and threatening users who did so.

I’d be interested to have OP crunch some data on that period, from before the season. Some data (like how many users were just driven away by the suppression and being made unwelcome by the sub) may be impossible to get.