Yes.
No.
I agree with OP's point that there's too much negativity, but I don't agree that everyone who is negative should leave. Both can be true and OP can make a good point and bad point at the same time.
The point of a forum is engaging discourse, and it's no fun if everyone who's not with the 'correct' opinion is banned or leaves because then it becomes an echo chamber. At the same time, it's ALSO no fun if everyone is constantly on the same page of shitting on everything, because that is ironically a path to an echo chamber as well. We all have real life issues going on but GAF shouldn't be treated as a personal therapist couch or a pillow to scream into. It's about the enthusiasm of gaming, both bad AND good. The unfortunate problem is that a lot of people, whether they like to admit it or not, log onto this site with all their problems built up on their shoulders and lash out. It ends up being a stack of negatives.
There should to be a point where we reach a better balance to things if we want to be seen as better than two other websites I can think of. OP pointing out the level of negativity should be seen as more of an internal wake up call rather than a combat challenge to shit on him. He worded the message somewhat wrong, but the bigger message should be understood for all to see and all it takes is an extra minute to really take what he's saying critically instead of combatively.