Ethically, John influenced Matt's belief that he needs to kill himself. Sure Matt could've not killed himself, but if he killed himself on just someone saying "Kill yourself" they were thinking about doing it anyways or they were swayed strong enough to actually do it. Since John said "Kill yourself" it influenced Matt's belief that he has to kill himself which is considered murder. It was the influence not the result that is unethical. Judicially, this would be considered murder if they saw evidence of John saying "kill yourself" and Matt did. John would be convicted of murder.
Both. He factually killed himself yes, But John influenced him into doing it so it is also indirect murder.
Suicide is inherently, unless under extreme external duress, a personal decision. Calling the encouragement of others murder, while it's certainly unpleasant, is a downright silly oversimplification of psychology and human interaction.
It's not illegal to tell someone to kill them self.
He didn't have to kill himself. He could have chose not to...
This is a ridiculous question.
he did not murder him, he did not force him to do it, it was his own choice to kill himself.
If John tells Matt to go buy and apple and then Matt buys an apple, did John buy the apple? No. Matt had a choice of whether or not to go buy the apple, John had nothing to do with it. Sure, John played a very prominent role in Matt buying the apple, but John did not have Matt at gunpoint, forcing him to buy the apple.
Matt could've written John off as a stupid person with very poor conduct, ignore him, and keep living his life.
Clearly Matt undertook suicide - the question is whether John was a murderer. Assuming Matt's suicide was entirely motivated by John's speech, John did not cause Matt's death directly. However, his action was still immoral. If an elderly person slips on a wet floor and dies from their injuries, is it the janitor's fault for not drying the floor? Technically yes, but you wouldn't call them a murderer.