"The First Amendment exists to protect free speech in the United States,” said the court’s opinion, which was written by Judge Douglas Ginsburg. “Here the Government acted solely to protect that freedom from a foreign adversary nation and to limit that adversary’s ability to gather data on people in the United States.”
They've determined that it's not a violation of free speech because China, and that it's not a bill of attainder because China. You could replace "China" with anything.
What does it mean to be a "foreign adversary?" When did voters get a say in that? When Democrats (and every media outlet) were accusing Trump of being a secret Russian agent, and people who supported him of being traitors, would it have been legal (and not a "punishment" but a "prophylactic" as the appeals court said about TikTok) for the legislature to limit their free speech by name?
https://en.wikipedia.org/wiki/TikTok_v._Garland