I could hazard a few guesses as to why somebody might do that, but given I don't run a forum and have no intention of giving up any time or effort to do so I can't be bothered to speculate.
Frankly though, beyond the odd "oh, that's a shame, I liked their posts on XYZ" there's precious few...
It's important to maintain a level of plausible deniability to avoid further economic sanctions and possible direct intervention from the UN or NATO.
This is the Russia invades Ukraine thread, right?