What do you mean by "others can't"?
They don't want some things even if they're operated domestically by Americans, but it looks like per OP, they're fine with people/political PAC's/Political Parties buying literal 'influence campaigns' for ideas that prop up the status quo.
https://www.nytimes.com/2018/10/11/technology/fake-news-onli...
Why aren't they removing all pseudoscience in this case? Why not astrology, why not psychics, why not tarot card readers, why not people selling weight loss drugs, why not people showing videos of 737's recovering from a barrel roll on short final, why not homeopathy, hell why not literally all religion?