A person can claim to be something without actually being it you realize.
It's called either:

a) Lying
b) Lack of understanding on what they call themselves

Just because a person claim's they're ________ doesn't mean they're blank.
Hell often times with Religion people would claim they did ________ in the name of God. But they were furthering their own agenda's instead.
You can do this with anything, feminism, being a nationality, in support of a certain cause, a democrat etc.

Religion also gave incentive to keep people from being literate, it was a means of control. The less people could read the more they could be ordered on what to do instead of learning things for themselves. Also just because a few Intellectual's happened to be Religious (especially in a time when Religion was established fact among most people, so almost everyone universally was religious) doesn't mean Religion aided progress. It simply means it's not impossible for a religious person to want to progress knowledge/science, and it does nothing to change the fact that countless scientific work was burned/lost/prevented due to Religious fear, hatred and paranoia.