Earlier quoted context omitted.
They absolutely support their practices by doing business with them. Not only did they list their game for sale on their store, they took their money (earned via those business practices) to give them the exclusive right to sell the game on their store for a period of time. This has the goal of driving even more customers to Epic. They don’t do these deals out of benevolence.
Have you bought a Nestle product? Is so you support child slavery. By your logic: > You absolutely support their practices by doing business with them. Life is not black and white.
Whether or not you choose to adapt your purchasing decisions based on this knowledge is a separate question of your ethics and other factors.