Deleting your account, does it really?

So this is more of a question if anyone is willing to answer, but why do certain apps like for example Reddit and Discord have a Delete account features but in reality it just removes your username from existence, unless you manually delete every single message, comment, etc. yourself it will remain there until God knows when, isn't it supposed to go against the privacy act or something (can remember the exact name of the top of my head). I …

account apps delete discord etc features message privacy question reality reddit single username