Election Interference so blatant that the EU started formal proceedings.
Multiple studies, including a very recent one by Rutgers and NCR, showing it's a pro CCP propaganda vehicle.
It lied about collecting precise user data.
The problem with TT isn't it's content, the "food pictures and people being nice to each other" you referenced, its with how TT uses its algorithm to influence its users and the risk of them misusing the data their app collects.
I dunno about this; IME even when it was highly approachable most people didn't do it. I was around back then, got my first Commodore in '84, and even the Geek / Nerd circles were mostly just for people swapping copies of commercial software. It wasn't any better when I graduated High School in '91 and even in College almost no one outside of STEM was doing any programming.
It wasn't and still isn't a popular activity.