> Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
The Constitution does not consider Freedom of Speech a positive right, one that can be granted to some but not others. It is a negative right against the government. It's about as broad and as absolute as you can get. This is why the right also applies to legal entities (eg: companies), even foreign legal entities. It is not limited to citizens, it is not limited to persons.