If TikTok is doing something bad then the bad thing should be illegal, not the platform or who owns it.
But banning bad things would require a well-thought-out bill that could inadvertently protect Americans from domestic tech companies that are also harvesting and selling our personal data and manipulating our attention. And that would be a problem (for politicians).
Easier to just blame China and kick the can down the road to the next generation to deal with the real problems.