Religion in a Vacuum

Thoughts.

Many people think they can understand something like religion from within a vacuum consisting of only what they believe.
Isn't that like taking something completely out of context and basing it's truth simply on the single statement itself?

Not to cause confusion, I firmly believe that Jesus/Yeshua is the messiah to the Jewish nation and the other nations/goyim/gentiles are able to be grafted in. etc., etc., etc.
BUT 'Modern Christianity' that claims that it is true simply "because it is true" strikes me as a logical fallacy (see "begging the question").

I know, I know, people say just have faith. I don't buy it though. Yes, have faith. But not as a founding reason to believe.

Thoughts?