On top of the many reasons listed already, one needs something to hate at all times. Vita and Wii U hate seem to have played out already (hopefully), xbone can also be cut some slack now after many hard months. You can't pick on ps4 without angering the entire internet.
So, that leaves Watch Dogs. There was one preemptive hate thread about Destiny too yesterday. Something to look forward to now since Watch Dogs is out.