Because Trump wants a proxy so he can continue to influence the direction TikTok takes. He wants easier access to data so he can go after his political opponents, as well as get things censored he doesn't like. Of course, this would all be possible without someone on the board, but it can't hurt, and likely will help.

If TikTok removes something, would the fact that there’s a government representative on the board give standing for a first amendment claim? Normally private companies aren’t required to furnish you with first amendment rights, but if one could argue that, if not for the board representative, they might not have prevented that speech, then perhaps you would have standing.

Yeah, the supreme court will get right on that

As soon as the appointee is appointed by a Democratic politician, at least.

That won't help. The count is currently 6 Republicans to 3 Democrats. The party isn't an absolute predictor of how they'll vote, but it's pretty close.

It would take a minimum of two Republicans to retire, and be replaced by Democrats, to change the partisan balance. The oldest justice is Clarence Thomas, but the next two are both Democrats. Everybody else is under 70 and will not retire for a minimum of a decade.

I'm talking about the appointee to the board of the US-TikTok; I doubt the Supreme Court will have any objection until it is favorable for their partisan politics. (I hope I am wrong, but the past years have made me quite cynical)

When has this government give a single care about free speech or the constitution or even the law in general?