Note that 1. this is mostly regarding the Steamworks SDK that you link to; sufficient care may be taken to try to make this linkage to Steamworks "compliant" as noted in the article, and 2. this is about GPL, not LGPL. Distributing LGPL code via Steam may introduce some potential murkiness, but it should be mostly kosher since I think Steam doesn't, in and of itself, impede on the user's ability to exercise the rights granted by LGPL.

Right, sorry, forgot that. Edited!

Games and applications distributed on Steam don't have to integrate with Steamworks SDK at all, and when they don't this licensing issue doesn't apply.

You dont have to use Steamworks to be on Steam.

There are a lot of games under GPL on Steam.