I'm just middle aged and lost all energy for unproductive discussions. The second another poster posts something genuinely hostile, like "touch grass" kinda shit, I'm just done talking. Also if we're six comments in and the other guy won't even admit to being wrong to the thing he said on comment one, despite me doing twenty minutes of research to prove conclusively that he's wrong, I don't want to waste another second of my life on him.
I gotta have 10% of the "disengage" comments on this site.
Saying you want to disengage isn't just for you, it's also a signal to the other person that you have no interest in talking to them and they shouldn't waste their time either, not just yours. If they respond to a "disengage" with some smug comeback, they're just wasting their time.