Why has this come about with no warning, if not to upset the natives? When the natives get upset, why not at least try to give a convincing explanation consistent with the actions? There are better ways to get user buy-in than hacking them off off.
The forum is nothing without its users. I dont understand why you're seemingly going out of your way to alienate them?
PPRuNe will go on, of that I have no doubt. However it wont be the same, and wont be nearly as valuable or interesting a resource.
As shack says, If you have a traffic problem, only allow registered users to view the forums.