What they're talking about here is the use of Steam as a copy-protection system, which is completely integrated into a game, including the retail "disk" version.
When one installs it from a disk, it first prompts you to either log into steam or make a steam account, and then it installs the purchased game into the Steam folder and activates it on your steam account. The first games to do this were official retail release of Valve games, but since then, many other games have implemented it due to the various advantages of using Steam in your game (good copy protection, Achievements/stats tracking integration, ease of updating, multiplayer server browser, etc).
What they're trying to say, essentially, is that these "other" retail games are promoting their competitors, and they don't like it.