I get that people feel hurt by the fact that the show is still running when they have witnessed what they believe to be a precipitous decline in quality over the years. I get that others continue to watch the show hoping for an increase in quality, and are bitter when they don't see an effort on the part of the writers and producers.
I don't think it is invalid to dislike the Simpsons, or to think that new episodes suck. I watch episodes or individual gags in episodes sometimes and feel embarrassed for the writers. I remember feeling this way viewing some classic-era episodes when they premiered. I also sometimes watch new episodes (like tonight's episode) that are excellent, and I head over to NHC wondering if anyone likes the episode as much as I did, or if everyone still thinks it is trash.
I don't think any of us will have an accurate, somewhat subjective view of the overall level of quality of The Simpsons until long after the last original episode has aired. Our feelings of nostalgia can cause us to give a free pass to crappy episodes, and our feelings of bitterness can cause us to overlook hidden gems in even the worst seasons. Often, I have disliked an episode when it first aired, only to later see it in syndication, perhaps forgetting it was a later episode, and find myself laughing the whole way through.
As I said in my original post, I am not a fan of every Simpsons episode, and I know plenty of people who no longer care for the show, but they don't spend time virulently complaining about it online. Many people here have a fixation on the show's decline in quality.
There is nothing wrong with this negativity, in that it hurts no one - but all this negativity turns a community full of Simpsons fans, with lots of knowledge about a show that we can all at least agree was once a classic, into a forum full of negativity and sometimes what seems to be outright hatred, personally insulting the writers and producers of a cartoon show.
Even those of you who hate the show in its current form may perhaps agree with me that on some level, the negativity gets way over the top on this forum. There is no solution for it - as you so aptly recognized, people here aren't going to let a couple of first or third-time posters tell them how to conduct themselves.
I think what will happen is that three or four years after The Simpsons ends, the negativity here on NHC will go way down. People will no longer be calling for the show to be canceled, of course, but I also think there will be a renewed appreciation for the series as a whole in some cases, and at the very least, renewed appreciation for the classic era, untainted by the bitterness that currently pervades the board.