1. Most of the posts on they sub have nothing to do with people's lives being "ruined".
2. Yeah its may be unhealthy but people do all kinds of unhealthy things to themselves.
3. 35k subs on a subreddit that seen around 12 years is TINY. There's a sub about quitting porn that has over a million.
4. Even though you claim there are "no studies", here's a study from the WHO. Where they concluded that no action beyond "monitoring" was warranted based on current evidence.
https://www.who.int/publications/m/item/kratom-mitragynine-7...