What happened to digital footprint?

I posted a video about current political issues and got a comment threatening to deport and 🍇 me (ik… such a compliment! 🤪) ummm anyway, his name was in his user and I found all of his information. So my question is…why are people making these type of comments publicly? with their public name? do they not know we can just search them up?!?! Like in general i keep on seeing younger kids posting that they’re drinking/smoking n like cool.. BUT WHY R U PUBLICLY ADMITTING THIS? Whatever weird rant.