This is happening to us here. I think they're doing it by using the "No true Scotsman" informal fallacy and other methods. We'd blame the hundreds of thousands of new users. I believe they've found a way to unwind this community. Nothing revolutionary will ever come from here (how could it?). I think the community has been compromised and that we won't find out until 50 years from now when most of us are dead.
This is how I feel after years of watching the community. I have no stake in it either way. I'm open to opposing views.
Thanks vermontdevil for finding the link. If in 1944 they had a field manual for subverting physical organizations, it's foolhardy to believe they don't have a field manual for subverting "online communities with up and down arrows."