There is a ton of negativity, it's true, but then again the front page is a wasteland. I rarely check it. The "anonymous asshole" factor is so much huger on the front page than it is here. Plus when a good news item comes up, someone links it from here.
Still, to your point, I think you have to look at the quality of negativity, as it were. The vast majority of critical comments are, as you said, moronic. Who cares? It's no more annoying than graffitti scrawled on the wall of a public latrine. The fanbase isn't negative, it's just mostly made up of (I hate to use this term) a silent majority. You have to visit this site with a strong bullshit filter, which most of us have. Happiness writes white, as the saying goes. How many different ways can one profess admiration and love for a pop singer? For every idiot who bothers to badmouth Morrissey here, there are twenty who remain lurkers because it's not terribly interesting to create an account, log in, and write "I simply adore 'Half A Person'!".
On the other hand, yes, there are a lot of posts that are clearly not written by morons and yet they're critical of Morrissey. These types could be considered a problem. But these people are just as much fans of his music as the rest of us. They haven't learned how to be Morrissey fans, that's all. I don't mean there's a "club" or a book of rules, merely that you can't really be a fan of Morrissey the way you are of other bands because Morrissey is totally different. I imagine it's confusing to many people, especially those of his new converts.
Take concert cancellations. I myself have had the misfortune of paying good money to travel to a city to see him play live, only to have the show canceled hours beforehand-- in fact, while I was standing in line to get into the venue. I was angry but it wouldn't have occurred to me to go online a day later and bitch about the experience. Morrissey is not a career music guy. He has always been up front about his emotional and physical weaknesses-- that's precisely why most of us like his music-- so to suffer the occasional mishap is to be expected. He works hard and comes through most of the time, but he's not a machine. We've all seen "machines" play live and for me, personally, I've often been so bored by those acts that I would have preferred a cancellation.
Most of the criticism I've seen (I mean, again, the 'serious' criticism and not the "f*** u, your shit!" variety) is almost always from newer fans who don't know better or older fans who just haven't learned the above. To the fans who moan and complain, if you want an official site, with a fan club, newsletters, special promotions, and a band that runs itself with the slickness and efficiency of a corporation, go to U2.com. Otherwise, roll with the punches. By being himself-- no matter what it means to the fans in terms of money lost or time wasted-- Morrissey gives the fans far more than any other artist. Paradoxically, in my two decades of loving Morrissey's music, when I think about what I mean to him as a fan I imagine myself as being no more important to him than an ant on the sidewalk and a vitally important person in his life. It's the most unique artist-fan exchange in pop music, intimate and alienating at the same time.
Some fans don't get that. They'll whine and yell but they'll still see him live, still buy the records, still pick up the t-shirt and the book and the DVD. The rest of us simply have to deal with others negotiating the Morrissey learning curve and hope they wise up fast. The point I'm trying to make here is that all these types are still fans. The fanbase isn't uniformly "bitter, nasty and negative"-- some of them are but most of them aren't. The bad apples are mixed in with the good and we just have to live with that. I have rarely despised a contributor on this site but when I have it's usually because they're trolls. When I wade through the front-page muck I just remind myself: they wouldn't be here if they weren't fans.