Tolerance of dissent is patriotic.
That way, everyone gets to say what's on their minds.
Free speech isn't required to be pleasant. Courtesy would be nice, of course, but it's not always invited to the party.
If someone doesn't like what another person says, fine. The reply is obvious: "I don't like what you said, because..."
Or: "I disagree with what you said, because..."
A step down: "You treasonous pig! How dare you hold an opinion which doesn't support American policy?!"
It's easy to tell the difference.