Capitalism, excluding the free-market part of it, isn't legal.
Let's say a small population lives on a small island. Someone comes in and somehow purchases all the land. He asks on the inhabitants that they either become his slaves or produce their own land. The inhabitants can't obviously produce land, so they'd drown in the sea. They have the choice between being enslaved by someone who didn't produce any wealth, or die in the sea.
This situation is what's call extortion by the exploitation of the cost of producing redundancy, and that's also capitalism. Just someone owning land, natural capital, and seeking a compensation for its access and under the threat of being forced to waste resources replacing it. Or die if they can't.
When you produce a game, you are warranted to a compensation for your labor. However, the reproduction of your game by computers and the transfer through networks isn't of your doing. You can sell one game copy legally, the rest is extortion. Once you have consented to the production of one game copy, or one game update copy, additional transfers of that game doesn't increase your cost, and thus doesn't warrant additional compensations. If you withhold the game after consenting to a compensation, you exploit the cost of replacing it.
If people don't pay you, then you won't be willing to produce a game. If people desire your game, it's advantageous for them to pay you. I myself pay of a patreon because I want it to exist. Once you've consented to a compensation for your labor, that's all you deserve, that's fairness.