Amazon actually does have these sorts of restrictions but they either don't work or Amazon doesn't do a good job of vetting the "approved" sellers. Some products (and some categories) are "gated" which means you need to get permission from Amazon to sell certain items. I even think the "official" listing for Mag Safe charger is actually gated. The only thing is there are 10 or (seems to be duplicate) listings for Mag Safe charger that are ungated. Some sellers are allowed to create listings too, thus getting past Amazon's restrictions.

It's pretty obvious Amazon just doesn't pay enough attention to the products that are sold on their website. Or they intentionally turn a blind eye. They had a bunch of listing for prescription drugs[1] and Amazon.co.uk was selling weapons that were illegal in the UK[2] for just two other examples I could think of off the top of my head. Oh yeah, and they sold cyanide, too.[3]

[1] http://www.slate.com/articles/health_and_science/medical_exa...

[2] http://www.businessinsider.com/banned-weapons-being-illegall...

[3] http://articles.philly.com/2015-09-05/news/66217129_1_cyanid...