This helps you build up an immune system that is skeptical. If most wrong answers were removed/flagged/hidden then the remaining wrong but unflagged would be even more a problem.
Good for debate and free speech in general, but bad for your grasp of the facts in the case every time there don't happen to be any corrective replies.
Hard to weighs pros vs cons.
(ObSillyPun: Naah, just put them on the scales! But remember that a lighter pro will often beat a heavier con anyway!)