OK, that's a bit of an overstatement. When confronted with a meandering, vague, or poorly worded post, "what's your point?" is a perfectly reasonable reply. (Although just ignoring it is also a perfectly reasonable action. If you do reply, some encouragement toward clarifying might be helpful: "I can't tell what you're trying to say. Could you clarify?"
But I'm getting very tired of "What's your point?" replies used to mean "I disagree with your point, so I'm going to try to pretend that you don't have one", even when the point is perfectly obvious to any objective reader with a halfway-decent command of English. It's either a cheap, dishonest rhetorical trick, or it's a mark of someone who's so committed to one viewpoint that they cannot conceive of another viewpoint even existing, let alone being valid.
That use of "What's your point?" needs to die.