LAWS are involved in this decision, people, as well as the fact sponsors bring in money and even if there's a visual benefit of that sponsorship that only a section of the Gaia userbase gets directly there's an indirect benefit for the whole site and all the users on it.
do you all understand the basis for international copyright and regional licensing issues? do you know any of the valid reasons that caused international agreements and laws regarding them? sure, they can be a fuss, in some instances they don't always seem fair to everyone, but sometimes it's impossible in life for things to be fair to everyone.
so Gaia gets a sponsorship opportunity like this, they could make money on it even if they have to limit who can directly access it. Gaia has some options on how to deal with this.
1 - take the opportunity but make the benefit available to everyone, even if laws require otherwise. they make an initial profit that helps the company the money to keep the site up and improve on it but they risk getting sued for much more than they make which COULD get the site shut down.
2 - pass up the opportunity and we see no nice new items we'd not see any other way and Gaia misses out on a chance to make a lot of money that would help the upkeep of the site.
3 - take the opportunity, follow the law and limit who can directly access it if they have to, but if there's a way make it so that even those who can't directly have it won't be completely left out (by making sure they could allow secondhand sales in this case instead of having the items be soulbound so only those in the US when its being sold can get them). they make money and everyone gets some chance at the items even if some can't spend RL money on them.
option 1 is definately unfair to Gaia and could hurt all the users as well, option 2 is unfair to both Gaia and everyone especially given people have been wanting more FMA themed items for a while in this case, but option 3 benefits the most people.
in all three cases there will be people who are unhappy, but that's how life is. you can bend over backwards, do as much as you can to try and keep people as happy as possible and there will always be people who still act like you pissed in their cereal. a company can only try to keep as many people happy as possible and still keep themselves healthy as well.
you can play dog in the manger all you want and say they should have went with option 2, but this is real life and Gaia is a business so fluffy ideals that work better in theory than in practice don't hold and 3 is logically the best option.