
A man who preached about kindness towards animals, plants, earth and all living things can not be a man who spread Islam by the sword.
He (peace be upon him) had mercy and compassion even unto his enemies, because as God tells us, as well as our tradition shows us, that he was only sent as a mercy to all mankind and to perfect good character. He was (indeed) the best of creation.
“So by mercy from Allah, [O Muhammad], you were lenient with them. And if you had been rude and harsh in heart, they would have disbanded from about you. So pardon them and ask forgiveness for them and consult them in the matter. And when you have decided, then rely upon Allah. Indeed, Allah loves those who rely [upon Him].” [Quran 3:159]