Laws don't stop criminals from being criminals (except when they do of course), but it isolates them so they can't easily blend into the crowd of non-abusive in

Laws don't stop criminals from being criminals (except when they do of course), but it isolates them so they can't easily blend into the crowd of non-abusive individuals. Plus, if something is illegal there's less likely to be an industry driving down the price of that activity. If something is more expensive and less convenient, then people (including criminals) are less likely to do it.