Why are these forums full of complaints and negativity?

[Arriverderci]

Because people mistake feedback for complaining.
There are some glaring problems in this game y'know.
Legitimate concerns SE needs to look into.
Now, the posts like, "Read up dungeons and qq people in Duty Finder noops horror stories."
Are just silly lol.
People who are generally alright with the game are playing though.
Also this:

"Why are these forums full of complaints?"

There are lots of things to complain about...