The thief would have to prove that they were harmed by a particular person. Meanwhile such attacks are in public places people are moving through hit and run style. Police response times are long on non-emergency issues and the last thing the thief wants is police contact.

A: The thief doesn’t call the cops B: If the thief does call the cops the person is gone, C: If they follow you are being followed by someone who tried to harm you pepper spray them D: the police do not meaningfully investigate the thief’s claims if they are alone E: if both parties are present the police don’t care about petty crimes they didn’t see and therefore can’t prove so let everyone go F: If you got harmed reaching into someone’s purse they are liable to prosecute the thief not the victim if anyone especially if they admit they had their hand in your purse G: if the thief does try to sue its in small claims court for actual damages which are small and creates a record of their identity allowing you to popularize their face and identity in the local area as the thief who sued his victim. Seriously start putting up posters with their face around the area. Loss of illicit revenue will be higher than gains. Hopefully they also get stomped later.

Since all of these things are implicitly obvious and most importantly the first rule being a hood is avoid police contact we basically normally always stop at 1.