This description applies to me also: a conservative member of a liberal message board, posting frequently to illustrate how wrong liberals are.
My goal is not to get under anyone’s skin. My goal is to see how well my ideas hold up when subjected to strong criticism. It’s not useful for me to say, for example, that I disfavor same-sex marriage on a conservative board, because I would get nothing but laudatory responses and agreement. Posting the same thing here made me work to defend the claim, and indeed to realize that it’s not defensible. So I abandoned that view.