Yeah, great question! I didn't really address that part.
What I really meant is that I almost never "win" the argument. I've overtly changed someone's mind before, but that's like 10% of the time, at best. So making that my goal wouldn't be a good idea.
More often, I can get the other person to expand their point of view, even just a little bit. I can gain some credibility in their minds as someone they may disagree with, but can respect. And it opens the door to the perception that maybe the point of view I represent isn't directly opposed to their tribe. For people I tend to debate repeatedly, I can tell there's a shift over time.
Not to mention the fact that I'm not always right. I learn a lot from people who aren't already inclined to mindlessly Like everything I post. Debating people makes me a better thinker and persuader.
But I think most importantly, I do it for the audience. I suspect that in many of these debates, the lurkers are much less entrenched in their point of view than me or the person I'm debating with. Those are the people I really want to move. And that's a big reason why it's crucial to be civil, sincere, and avoid blowing up on people. Nothing turns off a neutral onlooker like someone being an asshole, even if it's righteous.
