As a general policy, I agree with this.
I often find the exercise of "debating" to be... unproductive.
Not so much that I don't think I can't learn something from it. But then, you can learn something from almost anything if you really try.
I think the trouble I find is that a lot of people who wants to debate me is that they don't seem interested in learning. They just want to hang on to their side of the opinions for all it's worth, even when I show them to be incorrect. (If they are correct, I don't mind accepting it. But then, I also don't care for debating.)
Some will say, "But that's the point of debating." Maybe so, but if that's the case, then I find the very exercise itself to be unproductive. After all, when it's all said and done, what will you have accomplished?
Yes, there are times when debating is appropriate and even necessary, but not most of the time. Most of the time, I find that it is best to stick with the policy of keeping an open mind as much as possible, listen as much as possible, and learn as much as possible.
We should not be defined by what we think. We should be defined by how willing we are to think.
And if anyone disagrees with that, I'm ready to debate this for all I'm worth. Just kidding!
But seriously, were I in the OP's shoes, I would basically ignore him. The way I look at it is that, regardless of the outcome, it still doesn't change the amount of my pay.