It’s because it pissed off the wrong people. The initial push to ban tiktok was by Trump and republicans after TTers organized a mass RSVP of one of Trump’s events and he spent a lot of money on extra staff and ended up performing in an empty stadium.

That failed and Trump was mocked. 4 years later, it was used to counter zionist propaganda, and that got the democrats on board. Here’s Blinken admitting as much.

Additionally, Insta is TT’s biggest competitor, and FB, which owns Insta, lobbys to the tune of 20M/year.