Amazon only controls their market. You play by their rules if you sell with them, and that is totally valid. You can sell your product for any price you want so long as you don't use Amazon or don't undercut them if you choose to use them.
That is totally valid. Amazon provides the eyes; they don't want to provide a service for free. Think of all the people that go to best buy to feel a product and then buy it online. Amazon doesn't want that to happen to them.
That's the point. They are by far the largest player in the game, and can ( and do) use their size to squash competition. You don't have to use their marketplace but as a small business you don't have many options that can compete.
Hell, they're even extremely anti-competitive with their employees. Their NDAs are very restrictive and have threatened non-senior employees with them, even ones that they let go.
That is totally valid. Amazon provides the eyes; they don't want to provide a service for free. Think of all the people that go to best buy to feel a product and then buy it online. Amazon doesn't want that to happen to them.