Basically his discussion technique is one that 4-year-old could see through. You say something, he replies "that's dumb", you reply to that, he replies "that too is dumb". And so on.
He refuses to explain why the thing is "dumb", even when challenged, which almost certainly means he doesn't really know, he just slabs on that label to everything without thinking.
Since he is quite happy to do this seemingly forever, it is no surprise he often gets in the last word, people just have better things to do than correcting him forever like this.
Especially since he is willing to lie about the whole thing, and most people are not interested in reading such a quarrel anyway. This of course does not mean he is "right".
But he is happy to pretend that it does. For that sake, he is happy to pretend that he is right even when this for some reason does not happen.
In other words, he "backs up" his claim with troll tactics, which of course only means he is a troll.
