I was a bit pissed at first, but I was reading Oculus's own blog post about it, and at the end they went on about how this was a big step in making VR an affordable thing for everyone. Facebook said they don't intend to interfere with how it works on a gaming standpoint, and if they stick to their word and this buyout makes VR an affordable thing in the foreseeable future, I think this will be brilliant. I have faith in Carmack.
The reaction has definitely been a bit OTT, especially notch being a massive child and just cancelling Mincecraft for the Rift. This probably wont ruin it, if anything, this is just going to make it less of a niche product, and more appealing to everyone.