If it's not a new account and you have made a purchase with it (added steam funds or anything such while your billing address is in USA) then you can still activate the game using VPN but you will need the VPN running to play in multiplayer.
If the account is new and there have been no purchases made from a specific billing address, then use a VPN to activate it , then close the vpn and you will be able to play without it running.
This is the truth. If someone tells you something different he simply doesn't know what he is talking about.