If the investors came in expecting major growth (since this is not a business with a great monetization story) it's not surprising that there's pressure and turnover right now, almost a year later. And, it may well be that what's needed is a CEO with enough credibility to tell the board "you won't get that growth yet, we have some work to do."
Saying that to the board is obviously going to be hard to do for Ellen, or anyone in Ellen's shoes if they brought her in to deliver growth, and she promised to deliver that growth.
So, lots of drama, yadda yadda, but I would bet 100:1 that drama has, at it's fundamental source, intense pressure from the board, and I would also bet you that this kind of pressure is new for reddit as a company.
To me, that's likely at least some of the context for the rumors that Ohanian intervened directly to get rid of Victoria, the former AMA lead at Reddit. AMAs are one of Reddit's most visible branding / marketing measures. If you need to deliver growth, and aren't seeing it, it is completely natural to be looking at your premier product lines and trying to get them to do more. And, I would be surprised if this kind of thinking weren't informing senior management as they're struggling to deliver on these promises.