I will reserve a rant about some Harvester sycophanting on this forum, but some of the "fuck those assholes in Arcturus" folks have to like their music right? I understand they fucked over the promoter in a terribly unprofessional way, but that doesn't take away from the fact that they are one of the most musically transcendent and important avant garde black metal bands ever to exist. They push the envelope of what metal can actually be, and would have been amazing to have.
Therefore, I think the appropriate reaction for any fan of Arcturus at all should be disappointment. Disappointment that they would have handled the situation in such a way that they will likely never be invited back. And for those of you who wait for the announcement before you check out bands you've never heard before, Arcturus are amazing and should still be in your "to listen to" folder. Check out La Masquerade Infernale and The Sham Mirrors. Seriously, they're awesome. It just sucks that they've done this to our faithful leader. Just don't be so unwaveringly loyal to the Parrot-headed master that it ruins your chance to appreciate some of the most progressive music out there. Any "prog" fan should have some appreciation of what Arcturus has done musically.