That's definitely true, though I find that the less technical platforms are laxer. However, that level of quality control is exactly what keeps me coming back. If you ask a stupid question, SO is going point it out rather bluntly. Quora will give you a best-effort answer so someone can plug their latest product.

Ask a vague question on Quora, and you'll get a vague answer.

Ask a vague question on Stack Overflow, and you'll get downvoted along with comments to the order of, "You haven't provided enough information for us to give you an answer."