I would think the Bill of Rights applies equally to citizens or non-citizens. That includes the First Amendment. That includes the right to freedom of speech and expression of opposition to whatever he or she desires. The freedom of speech is part of the 'truths' that are self-evident. And almost every time, the Congress tried to restrict these rights, they were struck by the courts. This isn't about demolishing the state, as communists would want to do. This isn't about changing the constitutional order, as any totalitarian party would have to do. This is about a right of a person to express his or her opinion without repercussions.

"This case -- perhaps the most important ever to fall within the jurisdiction of this district court -- squarely presents the issue whether non-citizens lawfully present here in United States actually have the same free speech rights as the rest of us. The Court answers this Constitutional question unequivocally ‘yes, they do.’ ‘No law’ means ‘no law.’ The First Amendment does not draw President Trump’s invidious distinction and it is not to be found in our history or jurisprudence. … No one’s freedom of speech is unlimited, of course, but these limits are the same for both citizens and non-citizens alike.”

https://storage.courtlistener.com/recap/gov.uscourts.mad.282...