That's not a wholly accurate characterisation. The internet is regulated in China, in the same way that broadcast media is regulated in the US. You might vehemently disagree with the specifics of Chinese media regulation, but the regulatory principle is the same.
Foreign media companies that choose not to go through the Chinese regulatory system are blocked from operating in China. Google and Facebook have chosen not to operate in China rather than comply with their regulations, but many American media companies have, most prominently the Walt Disney Company.
There is a fundamental difference between having a legible and uniform regulatory system and arbitrarily banning companies based on the whims of the executive. If a Chinese company started beaming satellite TV channels into the US that flagrantly violated FCC rules, we would fully expect the FCC to take strenuous enforcement action. You or I might consider Chinese attitudes to freedom of speech abhorrent, but the regulation of Chinese media is a matter of Chinese sovereignty.