To be honest, I was mostly trying to short-circuit the "disagree -> downvote" cycle. If you want to convince people that they are wrong (not necessarily this one person in particular but anyone else he may have convinced), downvoting the explanation of their opinion so that nobody sees it is also guaranteeing nobody learns enough about it to counter it.

Real politicians do "opposition research" for a reason; they don't seal themselves into an echo chamber, despite the frequent accusations to the contrary, because they know they won't hardly last a week if they do seal themselves off from what their opponents are doing and saying.