Yes, I can blame them for that. When running a business you have to decide what your core principles are and which ones, if any, you are willing to compromise for money.
>And its not like they support their practices.
Taking their money and listing their game on the Epic store is an endorsement of Epic's business practices, just like listing your app on the Apple App Store is an endorsement of Apple's business practices.
By your logic:
> You absolutely support their practices by doing business with them.
Life is not black and white.
If Nestle is engaging in child slavery and you buy their products then yes you obviously are supporting child slavery through indirect material cooperation. Behaving morally isn't easy, which is why it's so rare.
Whether or not you choose to adapt your purchasing decisions based on this knowledge is a separate question of your ethics and other factors.
You can't blame them for taking time exclusive money, they are a business afterall. And its not like they support their practices.