What exactly is the problem? AFAICS its just a potential problem - there is a social media platform that is not controlled by an American company. Now you know how the rest of the world feels.
A lot of Americans have a tendency to think of their country as naturally owning the internet. I personally find it quite alarming.
I do acknowledge that the US throws its weight around diplomatically and tries to impose its laws as an international standard.
On a pervasive level, it's in the way a lot of Americans on social media tend to assume that all content is necessarily intended for or addressed to them somehow. For instance many people I know have had an American hate train jump on their tweets that were talking about one issue or the other from a local lens - as though we should be constantly filtering ourselves and our language to cater to America's sensibilities. I've never seen quite that level of arrogance from anyone else.