I wonder how many times you could get away with “Oh shit, sorry, my bad!” before they catch on. “I could have sworn the safety was on, I just instinctively turned around when I thought corporal dudley called my name.” “I know grenades are dangerous but I’ve always been such a butterfingers.”
Similar to what others said, it is about control. The US state has complete control over how the “algorithm” feeds people the narratives that the US wants to feed them when it comes to the major social media platforms. But not with TikTok. It is not a national security threat in the way they want people to think it is, but it is a national security threat in that they can’t force their curated propaganda through it as they see fit, like they can with the other platforms. It’s a propaganda liability.