You are creating a false equivalence here. China is not choosing what is valid or not. They are not preventing you from visiting any other platform. The US government, however, is stepping in and preventing you from visiting a specific platform.

Ideally I agree with you everything would be transparent and open source and we would all be singing hakunah matata.

But if the issue is an opaque system of AI Blackbox algorithms then why target TikTok? All social medias use the same exact principles.

unable to inspect it then I want the person who is able to do so to have interests that are better aligned with mine, either an elected representative or at least a worker with similar national interests to me.

So instead of deciding for yourself, you would rather hand it off to the paternalistic state?

Because newsflash- the executives of TikTok and the CCP officials behind them have less incentive to screw you than the American big tech executives and the federal officials behind them.

a matter of the book store instead of a single book

If we were to use your analogy, it's not a book store but a farmer's market. Anyone can set up shop and sell whatever they want.

Your stated issue is that the management of the farmer's market has the capacity to suppress or amplify certain items depending on their interests.

The problem I see is that what if the American citizen, being fully aware of the bias of this farmer's market, wants to go on there anyway?

Why should his right be infringed?

Note that the government used very specific language in the ban. There's a difference between a ban on speech based on the content and one that is content neutral.

For example if I ban a farmer's market because of a safety issue, that's a content neutral ban. If I ban because they are selling things I don't want, that's a content based ban.

The government is very explicit that this is a content-neutral ban. They claim in the legislation it's for the explicit purpose of preventing China from collecting data.

Of course, that is nonsense and the real reason is the same one you mention - a content-based justification. Why didn't they say it?

Because the legal scrutiny for infringing on speech for content-based justification is much higher, and the government would not meet that scrutiny.