Mentally stable people are not internally put off-balance by being told to kill themselves. I know that if somebody on the Internet told me to kill myself, I would find that either boring, or mildly amusing in the yah, sure sense. There is only one cause I can adduce for somebody becoming upset by being told to kill himself: He has actual suicidal tendencies, and his therapist told him that suicide talk is harmful to him.
As anyone who has ever played online games can confirm, if phrases like this actually meant anything the human race would have simultanesouly gone extinct
and experienced a major population boom from the number of people being told
"Kill yourself" and
"I fuck your mother" on a daily basis.