Re: How do they get away with it?
Corporate socialism. We've been doing that since the '90's. It's still very much in fashion. Bill Clinton invented it, Obama perfected it.
My real question was why organisations Amazon competes with who don't get these state subsidies don't sue and win?
If there is no equal treatment provision in this area of US law, that implies that the Government is free to rig any sector by differential taxation. You don't like Apple encryption policies? Impose a huge cellphone tax and then give specific breaks to Android vendors. That sort of thing is legal !?