I've got very mixed feelings on that.

I'm not entirely sure that someone should be able to come into another country as a non-citizen and go around drumming up support for our foreign enemies. I can tell you no other country on Earth would put up with that.

Whether or not the first amendment applies to non-citizens, especially non-permanent residents is clearly hotly debated. I can see both sides of it.

The almost perfectly clean split across the Federalist/Democratic-Republican line that the founders had on the Alien and Sedition Act I think makes pretty clear that even the founders didn't agree on whether or not it did.