Why can't an American (hopefully a Trump supporter) just copy the technology and make their own version of Tiktok?

It is somewhat unfortunate it has to be banned because it does have a very large presence of Trump supporters posting pro Trump videos, and as far as I know they weren't censored (ironically) for being Trump supporters. I do understand why it's being banned though. If only a Trump supporter could actually make a social media app that would appeal to the general population...