The first 3 caliphs and the Umayyads created a vast empire. Were any of these conquests justified, or were they all based on greed for land and war booty?
Allah (SWT) knows the intentions in the hearts. We can not take political propaganda as the real intention. Those rulers who opposed the Holy Progeny of the Prophet (SAWA) can not be trusted as their behaviour against the orders of the Prophet speak about them. If they were after spreading Islam not expanding their rule, they should have practiced Islam in their own life.
Wassalam.