There are obviously some restrictions on speech in every nation. However in the US the restrictions on speech by the state are far fewer than pretty much anywhere else and are enshrined by law. This is in stark contrast to other other Western nations such as the UK where there are far, far more restrictions on speech.

With regard to falsely shouting fire, there are no common misconceptions. The common understanding of the saying is identical with the understanding in the judgment, and that part of the judgment remains good law.

However, there is a modern meme that strives to obscure this reality by pointing out that the judgment reached conclusions that modern people generally disapprove of. This has no relevance to the issue.