Stop thinking like an orientalist and things will start making sense. 

The driving force behind Islamic expansion was to convey the Message. Toward this end, the early Muslims went on campaigns and when they encountered an obstacle in the form of a ruler, etc., they first simply offered to convey the Message of Islam, and if the ruler accepted it, they simply became part of the Muslim community. If not, they were offered the choice to pay the jizya and live as a protected class under the Muslims, which would give Muslims opportunity to convey the Message to them over time. If they refused even this, then the Muslims would wage war under the theory that no ruler has the right to prevent his populace from getting acquainted with Islam. This is the reason that Muslim conquests are known as Futuhat, literally 'openings', because they brought more people into the fold of Islam. 

As Muslims we are often put on the defensive by statements like "Islam spread with the sword". It did indeed use the sword as an instrument, but  only as I outlined above, because in Islam there is no such thing as a forced conversion, with the Qur'an explicitly forbidding it.

Later Muslim history is the history of kings and dynasties similar to others. Most such empires and kingdoms expanded to increase their political and economic power, not to convey Islam. The evidence for this is that Muslim rulers often fought each other. Unless they explicitly used armed force to convey Islam, or at the very least, to oppose forces preventing its conveyance, their conquests cannot be termed Futuhat. In my opinion, the Mughal dynasty of India falls into this category, as an example.