This is borderline FUD. You don't need to use Steamworks to publish a Steam game. With respect to games, most commercial licenses also have these same restricti

This is borderline FUD. You don't need to use Steamworks to publish a Steam game. With respect to games, most commercial licenses also have these same restrictions, e.g. Unreal Engine. This seems fine, GPL is probably not suitable here. I don't think Valve is going out of their way to harm anyone's freedoms. If you really want to release your game as GPL, then do the usual workarounds: use a shim which RPC's to the proprietary bit.