A distinction that sometimes gets lost is that winning a debate doesn't mean being right. I had a friend who did debate and quite often she had to argue in favour of things she was vehemently against, and won doing so. I wish I could remember examples, but there were a couple of things where she actually thought it was easier to argue what she felt were the wrong positions, because there were more rhetorical angles she could take, whereas arguing the side she actually believed would be more reliant on things that she felt were self-evident.