Yo.

Hater thread? Ignore. It will eventually get buried. Responding in any way just adds to it. The ppl that DO post in it most likely share that poster's mentality. They can go ahead and complain to each other.
As for so many complaint threads it buries the ones that actually should get some attention-- this is where SE's forum moderation is severely lacking. It's just how things are. They're not going to change anything unless it directly affects their revenue, and there's no way the vast majority of ppl are going to stop FFXIV based on whining that seem abundantly rampant across these boards.

As it is though, general discussion is less that, and more a place to submit irrational, and illogical grievances in the supposed form of "suggestions" that are clearly non-constructive. It's effectively destroyed much of the charm this franchise has, and I'm sure for that reason alone lots of players make an effort to avoid this place.

Edit: HakuroDK's observations are pretty much spot on.