It's pretty simple.
As the name suggests, they're a waste of time.
Sure, some of them are emotionally provoking, especially the race threads, but at the end of the day, it's just a bunch of (mostly anonymous) nobodies on a non-mainstream Internet forum.
What's the point of attempting to convince them anyways? The mainstream is not moving in their direction any time soon, and these guys would rather complain about reality than even discuss how to deal with it (never mind actually doing so).
And who wants to associate with people who'd rather complain than take action anyway? They'll just drag you down into pointless conversation, and prevent you from taking action.
So it really is as Tom Torero says. "Less talk, more action!"