US companies may enforce US law but they're not hiding the fact that they're US companies. Zoom claimed not to be a Chinese company while enforcing Chinese law for US users.
It's not really a "mistake". They were aware they lacked functionality to region block meetings and rather than reply to the Chinese government that such a request will not be possible to comply with for x days until feature is developed, they opted to suppress US users. That sets a bad precedent for future ambiguous issues.
To some extent there is a per-country copyright block. There are some videos not available in the US but available other places because of copyright claims. It probably has to do with who the copyright holder is.
