Most policies aren't the sort of thing that is going to attract broad popular support (or opposition.) Did you look at the opposition numbers? Who are the "shadowy powers?" Lawmakers say that China is the shadowy partner here doing bad things with Tiktok. I don't necessarily trust the US government on this issue, but I was speaking to a Chinese national last year, they asked me why the US was banning Tiktok. When I said "because China is using it to spy on Americans" they replied "Of course they are!" and laughed.

I think there are probably some people who are pushing this for self-interested reasons (American social media apps) but also I think the stated reason for the ban is probably the truthful motivation, and I'm ambivalent about trusting the US government and US corporations not to spy on me, but I tend to trust the US government when they say they are trying to stop China from spying on me. And if zero people spying on me is not an option, well, fewer people would probably be an improvement.