"The U.S. State Department is now requiring nearly all applicants for U.S. visas to submit their social media usernames, previous email addresses and phone numbers. It's a vast expansion of the Trump administration's enhanced screening of potential immigrants and visitors."

Does freedom of speech only apply to Americans? Can foreigners get penalized and denied entry for what they say on social media?

Freedom of speech is certainly not universal today and depends on the laws of a country.

I have yet to find out the deeper reason for this. One of the main reasons of course is to prove your identity and bolster it with a digital doppelganger, but this is hard to do for those who maintain pseudonyms and tweet / post under assumed names. A lot of accounts on Twitter are assumed names. Facebook, not so much, as per their real names policy.

[dupe](2^5)