The Conquest Of Makkah
I think it is because of the law of itmam-e-hujjat. The people of the previous prophets, who rejected them were punished by natural disasters by Allah SWT. And the whole nations were destroyed under those Adhab illahi. Qitaal fi Sabeel Allah (somehow called Jihaad now) was under the same law. It was the order of Allah. Our beloved Prophet MPH mostly fight defensively. Prophet’s defensive battles, like Badr, Uhud, Ahzab and Hunayn, were where the enemy launched an offensive against the Muslims. While battles like Khaybar, Mu‘tah or Tabuk, where the Muslim state was aware of the enemy’s plans of aggression, resulted in a need to strike pre-emptively as a form of defense. It is also because of Rehmah that not the whole nation was destroyed even after the conquest of Makkah.