The "circle jerk" claim is just the motto of people who don't like to be called on their online whining and like to pretend that "fans" can't handle opposing points of view. Nobody is fooled. The whiners and nitpickers desperately, *desperately* want people to agree with them. Which is why they post of course. Fans on the other hand tend to express themselves out of an outpouring positive enthusiasm. You like something, you want to talk about it.
It's not "fanboys who can't handle opposing points of view and need a circle jerk" and "whiners who are totally open to having their nitpicks exposed and corrected." Hell no. The whiners need the loving hands of those in agreement much more than the "fans" do.
Who "in real life" ever comments on something they like and then appreciates someone ripping it apart. "Beautiful sunset." "Yeah well I think it looks like a festering zit in the sky." Man this spaghetti is good." "Actually it tastes and looks like rat **** oozing through your teeth." That's idiotic. And if you did that in real life you'd be called out as a *******. There are ways to disagree, to have back and forths and even debates (and I've had literal debates in real life over whether a movie was good or not) but lets be real. If you can't shut up about why you don't like something online and don't want to consider any opposing points of view then chances are you're lacking something that an online discussion won't fix and maybe you should take a good look at yourself.
If you don't like being called out on that then do what I do and just skim the bull**** and interact with the people who are worth interacting with.