What does any of this mean? I really can't figure it out. I thought it was standard advice to never, NEVER log into anything which can identify you while you're

What does any of this mean? I really can't figure it out. I thought it was standard advice to never, NEVER log into anything which can identify you while you're using Tor (which is why the best way to do it is from Linux distributions on a stick). And the talk about Facebook fixing this "gaping whole" in their security... If someone could clarify all of this, or maybe provide a better link, I would be grateful.