I appreciate you being open to hearing other perspectives. I’ve had anxiety for my whole life, and while putting my hands in my pockets isn’t my go-to thing, I’ll sometimes do it. I’m not a psychology expert but just from my own experiences, I’d say when you’re in a situation of feeling stressed/anxious/etc. that it’s comforting to feel as insulated as possible and/or to “close themselves off” to feel less vulnerable, similar to people who always have their arms crossed. Maybe some people are touching themselves, I dunno, haha but I do feel like there’s a lot of people that just do it as a coping mechanism habit.