My Opinion
I’ve been a bit confused why I see videos with that gesture censored, I feel like that rarely happened in the media I consumed a decade ago. However, I believe this “phenomenon” is older than TikTok and its weird censorship.
I’d place giving the finger at a high 2, low 3 on offensiveness, definitely nowhere near gesticulated sexual acts. You can give a child shit for using it, but the occasional finger is something I’d expect from even a teenager.
Its always seemed to me to be treated as the most offensive gesture but once you get to like miming things you are beyond sorta simple gestures.