We're talking about facts, not what ifs. No non-Korean national can ever become an It girl or boy (maybe a Korean-American or Korean-Australian, but definitely not a person of different Asian descent).
I mean you’re kind of right though. There has never been a non Korean IT girl or boy to my knowledge. Being foreign will hold both of them back, but people continue to throw around the IT title so loosely applying it to idols who aren’t actually IT as it’s not only determined by viral fancams but selling power and influence. Right now the only IT girl is Wonyoung lol