The problem of many web-based businesses is, they can't decide (or don't want to) if they are more like the phone company, or more like a bricks-and-mortar business. If they are like the phone company, they are not responsible for guaranteeing that what you buy over the phone is legit, but they also don't get a cut. If they are like a bricks-and-mortar business, they do take a cut, but they get liability. It is similar to Facebook, Twitter etc. trying to sometimes act like a phone company and sometimes like a conference hall.

The reason is clear: they want to be compensated like a retailer or conference hall, but have the (relative lack of) liability of the phone company or the postal service, who don't make any claims that communications via their services are going to be honest, just that they allowed the two parties to communicate.

Gradually, they are all going to be forced by society (not only government) into one role or the other, but I am not surprised they are trying to put that off as long as possible.