Even ‘Citizens United’ is about otherwise eligible citizens being able to organize under an umbrella (and act under that umbrella) - not that the umbrella itself fundamentally has rights independent of the people under it. Though it has resulted in widespread abuse due to the ability to hide who is actually under the umbrella.
Foreign nationals making statements outside the US towards US citizens have historically no protection either - it’s why the NSA and CIA are in theory not chartered for domestic action, but have nearly carte Blanche outside the US. The CIA and US military has rather publicly assassinated folks off US soil for statements and actions that would be protected inside the US.
In fact, prior Supreme Court precedent heavily uses phrases like ‘the constitution is not a death pact’, and ‘yelling fire in a crowded theatre is not protected speech’.
Historically, foreign nationals have even been ejected/deported from the US for what would have been perfectly normal protected speech for US citizens, and it’s very common for visas and other entry documents to be denied based on what would be protected speech for US citizens.
Unregistered foreign agents tend to be locked up, deported, or hung.