This is fallacious.
China is an authoritarian regime, not a democracy under the rule of law. There are laws in China, but ultimately a corporation is subject to the whims of the Chinese Communist Party.
International free market trade is founded on reciprocity - you open your markets and I open mine, under analogous regulatory conditions. Can US companies such as Facebook or Google operate with the same degree of freedom that TikTok does in the West?
Furthermore, and perhaps more relevantly to your question of whether TikTok has broken any US laws, it may be that it has. I have a very limited understanding of US politics and law but I do know that (a) there's a trainload of highly complex national security regulations, (b) Executive Orders provide the President a means to "steer" the application of the Law, and in this case it may be simply a way of enforcing codes that have been applied very loosely or not enforced until at all now.
I don't know if the EO will hold ground or not, but if it doesn't, I hope the US (and eventually the EU, where I am a citizen) find other ways to legally challenge the abhorrent asymmetry in playing conditions for software companies in China vs. the Democratic West.