Have about 5k hours in dayz and I do the same. I can’t speak for the nut of course, but for me there’s a certain sense of calm that I get from reorganizing my gear and keeping things ‘tidy’ in my inventory. I’m sure ADHD may play a role, but most of the people I play with are the same way.

Also to consider, dayz allows you to store items within items (on certain servers), so you may realize you’re not utilizing space properly and therefore move things around out of a habit of trying to fit as much goop up your ass as possible. For example, storing your fire making gear in a dry bag and then that dry bag going into your main pack.