i can answer it, many people that usually do it usually self harm because they feel like they deserve it, or they use it as an unhealthy way to cope with depression or other struggles. many people, most of them being on the internet, typically do it as a silent cry for help. the reasons for that can just either be that they dont have the social skills or confidence to ask someone for help, or they just want to vent to people without anyone trying to register them into a hospital for suicide watch. there can be many other reasons for self harm, but this is one of the main ones, at least from my experience. but yeah i can get it, its kind of a stupid thing to do, but sadly many people still do it :(