After I got Steam running with the workaround mentioned here, I've got nearly the same problem when launching Team Fortress 2.
After starting it from Steam the "Launcher" pops up and after a few seconds it disappears with the following error in the terminal:
/home/user/Steam/SteamApps/steamuser/Team Fortress 2/hl2_linux: error while loading shared libraries: libGL.so.1: wrong ELF class: ELFCLASS64 Game removed: AppID 440 "Team Fortress 2", ProcID 5299 saving roaming config store to 'sharedconfig.vdf' roaming config store 2 saved successfully
Because of the similarity with the workaround I used before, I tried to execute:
directly before launching the game, but there is no difference.