You’re really not wrong, and I’m not entirely sure why you’re being downvoted. Thievery is largely a product of unfulfilled needs or unchecked hoarding of wealth, one could even argue that the latter is just a reaction to living through or fear of the former. An anarchist society solves both of those problems inherently. How do you steal what can be gotten as a matter of course? I feel like the smallest outlier doing such things in a community would just be a mild inconvenience and caught pretty quickly.