I did (Still do!) play games (a lot), but I don't think I could see other people (even non-humans) as NPCs.
I wouldn't go that far, as I wouldn't consider them NPCs either, but checking if they have any valuables on them is a different matter. Even today, in times of war, you'd check fallen enemy soldiers to see if they carry something noteworthy, especially anything intelligence related, if you have the leeway to do it. In this chapter's situation, it was also a personal matter since those goons were troublemaker targeting him specifically. Rei couldn't very well kill them, but freeing them from the burden of carrying their money is a suitable punishment.
