Can you provide a source for this? This is the first I've heard of anything like this and searching only gives results about the game delisting due to payment processor problems from a few months ago.
edit: after some additional search tweaking this is most likely in reference to Wolfire v. Valve, which is now a class-action suit.[0] The argument seems to be that Valve is engaging in anticompetitive behavior by disallowing developers from reselling Steam keys for their games for lower prices on other platforms, not selling the games themselves on other platforms. So this may or may not be what the parent post was referencing.
edit: after some additional search tweaking this is most likely in reference to Wolfire v. Valve, which is now a class-action suit.[0] The argument seems to be that Valve is engaging in anticompetitive behavior by disallowing developers from reselling Steam keys for their games for lower prices on other platforms, not selling the games themselves on other platforms. So this may or may not be what the parent post was referencing.
[0] https://www.gamesindustry.biz/wolfire-and-dark-catts-antitru...