It's not unfair. We're lucky at all that SOME retail CD Keys for certain games that AREN'T Steamworks games work at all.
And the game works fine in Windows 7. What problems are you having installing it?
"Booyah! Look out, LeChuck! Here comes Guybrush Threepwood's glowing sword of hot monkey vengeance!"
-Guybrush Threepwood, Tales of Monkey Island