Why do BF6 owners have to play F2P REDSEC to progress the Battle Pass?

Because they are thinking if you don't want to play REDsec you will pay the coin to avoid it and that is how they making money off you for something you already paid for. You bought this game so they can make money off you anything you want in this game other then playing it you have to pay and the people who wouldn't do this a least in their eyes you paid for the game and you paying for this game actually is what paid for them to produce the free version. They didn't want to invest anything on there end but profit