I spend a lot of time on Reddit and tend to forget how toxic some subreddits are. I spend most of my time on car, motorcycle, electronics, and such subs. Plus a healthy dose of cute cat pictures.
Indeed, Reddit is almost as diverse as the web itself. Likewise my favorite subreddits are /r/aww and /r/Justrolledintotheshop.
I love r/justrolledintotheshop ! r/shittycarmods is good too.
This kid is going to find his way on to 4chan one day if he hasn't already. I have no idea what kind of boundaries I'd be setting for my kids if I had any, but once they're teenagers effective moderation seems like it would fast become an unwinnable strategy. I agree with some of the comments that suggested that an open dialog about his behaviors and view of women was key. Obfuscation and punishment seem like a recipe for recidivism.