Illegal according to who?

The US? Why would China care, they are their own country with their own laws.

International courts? Who is enforcing those judgments?

If you do, please know that it is possible the people at the booth are just low level employees with no say in the corporate policy and while these companies do deserve your ire, these individuals don’t deserve you yelling or screaming. By all means let them know your opinion and tell them that version is not welcome at the parade, but don’t attack or harass the employees.