Distinguishing Mohammedans

This Stratfor report distinguishes various Mohammedans:

For starters, it is important to understand that "Islamist" -- not "Islamic" -- is the accurate term to refer to the militants' ideology, which seeks the establishment of a government that implements Islamic law. ... Beyond the moderate mainstream of Islamism are two types of actors -- radical and militant. The former espouse a radical agenda, but do not use violent means. ... there are "jihadists" who they seek to establish an Islamic state by waging a jihad (armed struggle) against the current regime. ... Although not all Wahhabis are jihadists, it would be safe to say that most jihadists are Wahhabi. ... jihadists are also a sub-category within the wider Islamist militant universe.

Unless you are a diplomat, I don't see why these distinctions are useful. It is not clear to me that there are clear differences between these various Mohammedan actors, or that the terminology is accepted.