Earlier quoted context omitted.
True, to a point. But how much control can Amazon exercise over what dodgy sellers sell (as long as it's not a human organ or living creature)? Sure, Amazon can kick them off the platform but by then, it's too late and the damage is done.
If Amazon was good about kicking off dodgy sellers, then there would be fewer sellers trying to be dodgy. Regardless, it's their store and so they're responsible for what takes place in it.
As another posted wrote, I doubt Amazon really cares about the dodgy ones until they're no longer an income stream or until they get a pile of complaints about one.