"I don't understand" in place of "I don't agree with." Everyone does it, I've said it too, I'm not too big a stickler for this. But two examples stick out in my mind.
A friend with chronic insomnia visiting his parents and having a bit different bedtime routine, goes to bed earlier, eyemask, winds down for a couple hours before. He says, "I'm trying this out to help my doctor rule out whatever causes he suspects," and his parents go, "I don't understand, just go to sleep, I don't see what the problem is." He says, "I haven't been able to JUST sleep in months, I'm seeing professionals to figure out what the problem is." They insist, "Just sleep when you're tired! I don't understand what's so hard about that!" and so on ad nauseum. Just say you think he's a pansy for wearing an eyemask or something, it doesn't have to be an argument!
I've been slowly reading a book where a liberal American pastor travels around talking to conservative pastors to work out why they like Trump so much. He asks them but never accepts their answers, saying that he doesn't understand how someone of his same religion can have a different political perspective. They keep telling him, and even though I find their answers stupid, it's more frustrating that the liberal pastor author keeps saying how incomprehensible it is and claiming he has no idea what makes them tick. Dude, you just disagree. You think they're interpreting the bible wrong. There's no mystery here. So stupid.
It's not just autistic literalism, it's a bad argument. Not understanding prevents you from being able to argue the topic. It's a fine way to phrase a vent, but if you seriously say it in a debate, the other side just hears it as idiocy. "What even is that, I've never heard of that" is just so dumb as an argument!
