Well maybe they could have mass emailed all members, you are correct there. But everyone makes mistakes.
Now then you say it is their job to keep the business online, Havent you just stabbed yourself in the foot there, because that is exactly what they are doing

If they did not resort to baning some IP's then the server would have got ddos attacked to death to the point where you would not reach any site at all.
I just think some people need to step back at times and see this through the eyes of the Staff of vb.com. Does everybody really think they are enjoying this happening? Do you think they want to mass ban IP's? Of course they dont, as you said this is their buisness and at the moment they are doing all they can to protect it.