A 12 year old doesn't have rights. Right or wrong, that's the law. Also, he's at a highly impressionable stage in life. No need to subject him to a convict trying to tell him that whatever crime he committed was somehow justified.
A 35yo visiting a lifer... well, he's an adult, he can do as he pleases.
You're mixing up my point about kids just like Outlaw. See my response to him.