Why does islam punish the people who called a teddy bear muhammad or speak bad about him, if he said this?

I am just a human.. he is not divine.. why do muslims condenm to anybody for insulting muhammad to the death? where is Merciful of God? I think Muhammad wont like to see those things.. he was patience according to hadiths.. I heard muslims always say Jesus is not divine.. if you dont recognize the divinity of jesus it's like an insult for christians right?