I might as well give my full opinions on the situation with Mystic, but I'll try to keep this from becoming a mud-slinging post.
The amount of stress this one man has caused this community is insane, to the point where it's only become clear in hindsight. The amount of stress the community tolerated from him helped to ensure that it would all end in a big blow-up like this. I am not blaming anyone aside from Mystic in particular there, staff or otherwise. As MI pointed out, Mystic's cynicism rubbed off on the rest of the community, and it's both dangerous and difficult to try and remove the highly-influential head admin. If done wrong, it could've fractured the community permanently.
In the aftermath of the initial explosion it very quickly became clear that there had been drama brewing in the staff team regarding Mystic and Rob for some time. The full extent still isn't known and much of what has been revealed isn't within the scope of this thread, but I suspect it will become known one day, like much of the drama involving Spazzo. Maybe that information coming to light will invalidate everything I'm going to say in this post, who knows. It is at least comforting to know those who will take hold of development and management will be highly unlikely to repeat Mystic's past mistakes. It will also be interesting to see what alterations will be made to the game's course in the wake of two former heads departing.
Rob's supporting of Mystic's actions was what truly shocked me at the time. I still had a decent amount of respect for Rob when the initial blow-up happened, so to see him sink so low shook me. This is partially due to how staff handled my own mistakes in the past, which often involved Rob specifically. In my experience he was far more practical than he demonstrated on his last night as admin. Mystic was nothing like that. I was not around to witness Mystic's moderation first hand, but their constant cynicism and insistence that this "wasn't their community" does not paint a pretty picture of it. Mystic took moderation very personally, and was willing to hold grudges for over a decade. Drama of this scale was bound to happen, and once Mystic was in a position of power there wasn't much anyone could do to stop it from happening. Speaking up against him or even in favor of him would warrant unmitigated rebuking from him depending on how he selfishly viewed your actions.
Once he was out of power he could've been removed from the community earlier, but with the earlier precedent of tolerating his actions set during his time as head admin and lead developer, nobody would've thought they had reason to. It took him finally going so far as to receive unprecedented backlash from the community and staff alike for him to be banned. Are the people who put Mystic in power to blame? No, they could not have foreseen this kind of drama, especially with how Mystic got worse over time from what I've heard. The only people to blame here are Mystic for being needlessly self-centered and Rob for encouraging and supporting his harmful actions.
My general thesis on this matter is that Mystic created deep systemic issues that would have been very difficult to resolve once he set them in motion without a drama explosion. I believe the community will heal given time, but it's up to the new staff to see that through. Thankfully, the new wind being blown into the sails of SRB2 has been refreshingly different.