Even more simple answer: they play the crap out of it, and yet there always will be a bunch of whiners complaining about something in such a dramatic way as if every little thing is a total catastrophe. You can't make a game that will please everyone. Give them more compact maps? "Oh, these maps are too small, CoD this, CoD that". Give them big maps? "Oh, I don't like to run for 5 minutes before getting killed". No Little Bird? "Give us our favorite heli back". Little Bird added? "Oh, this heli is a legal cheat, remove it". Etc, etc, etc, ad nauseam.
Bottom line, the game has 2 major problems, which is lack of actually big maps (although Season 2 made a huge step forward in terms of quality of the new map) and hit registration. Pretty much every other complaint is a nitpicky whining and nothing else.