Tiktok is all about Short attention span, whereas hacker news is longer attention span. I don’t expect too many tiktokers to go so far as to log in and down vote.
I literally both read HN a lot and watch a lot of videos on TikTok. And I also know many other people that like to watch videos on TikTok. None of whom fit into the mould you are projecting. And none of whom base their identity around whether or not they watch videos on TikTok neither.