Yes they are really free, freedom is not entitlement to your social media of choice. Americans are free to speak whatever they want on platforms that are available to them. They are also free to invent their own social media that doesn't have the same restrictions as the popular ones. The government doesn't interfere with this choice, but platform operators also have the freedom to not associate with certain customers.

Parlor is one option, there's also Reddit, Pinterest, Snapchat, TikTok, the *chans, etc. There are decentralized networks like Mastodon. Neither the government or social media companies can stop you from choosing any number of social media platforms (or other communication platforms) to speak on. That is simply not the case in China.

> Americans are free to speak whatever they want on platforms that are available to them

You can swap out "Americans" with "Chinese" and you end up with the exact same thing.

"Chinese are free to speak whatever they want on platforms that are available to them." So are they now free too?

No, that statement would simply be false. China's social media & communication services are monitored and the government forces all platforms to apply censorship or identify dissent, they are certainly not free to say whatever they want. Services that don't adhere to these restrictions are not permitted in the country (like Google).

China also pursues dissent beyond its borders. Zoom, a company primarily develops their product in China, actually shutdown meetings with foreign participants because they were related to the Tiananmen massacre. The US FBI has revealed a covert CCP program called Operation Fox Hunt to coerce foreign dissidents into either committing suicide or returning to China's jurisdiction by threatening their family in China.

Frankly the difference between the US & China in degree of freedom of speech, both practical and theoretical, is astronomical. The two could not be further apart and even the most glib comparisons don't track.