I came up with something like DH7 out of a rather irrational reason: that is, I hate disagreeing with people, and I used to especially hate criticizing people, but I also get (perhaps understandably) annoyed by people being wrong about things. So my typical strategy has been to point out the things that they are right about to them, and look for a version of their central argument which is right, whether because its claim is weaker and its area of interest is narrower, or because there was a logical flaw which was simple to fix.

I know there's at least one person who found my discussion style really irritating and started trying to make me argue 'against myself' and then point that fact out. But I don't get especially attached to most of the ideas or points I argue about, so I remember thinking it was kind of pointless that he did that.