A few hundred thousands, maybe a few millions at most. A drop in the bucket of internet users
If you look around, tons of communities have been getting banned/quarantined/etc. recently. It began years ago with literal hate groups like FPH or coontown on reddit, pedos on 8chan, later came pickup artists and incels, TheDonald, Chapo Trap House, then Apple, Amazon and Google banning Parler, YouTube and Twitter restricting Trump, and now, finally, even WSB. In isolation, every one of them is a drop in the bucket. But overall it's definitely enough to matter. If this continues, at some point everyone but the most boring will feel the banhammer somewhere. And the most boring aren't the ones producing content (aka generating all of the value).
Things that were problems have been getting banned. Nothing has changed, except it's a little more extreme right wing platforms now. That always generates a lot of noise, because they are loud people.
Except the overlap in many of those communities is HUGE. Each isn't a drop in the bucket, they are often the same drop