Faith basically means 'trust'. It doesn't necessarily exclude having reasons, even good reasons, for what is trusted. Each time I take a step, I have faith that the "law" of gravity hasn't been repealed. That doesn't mean that I don't have what I feel is good inductive reason for trusting gravity. It isn't 100% certainty and I can't really answer Hume's skepticism about the logical status of induction, but it's good enough for me in my daily life.
Some people honestly think that the design argument is persuasive. (I don't.) Other people honestly trust their own religious experiences. Still others honestly insist that science contradicts and discredits supernaturalism.
Lots of people believe lots of things for lots of different reasons. Their reasons might be very good or very bad, but even stupidity and credulity don't imply that people are lying.
Some interesting thoughts. We all have different life stories. We all are at certain points in our lives. I think people have to be open for possibilities. We should not let presumptions regarding certain people or religion itself draw us away from the Truth of God.
Being a believer does not mean you don't use your brain. I have to say that to believe in God is like having a bright sun shining in your life. I am not saying most people are misguided or wrong. Humans do the best, based on what they know / have experience with, to improve their lives.
This is what God says in the Holy Quran as He starts it, right after the opening chapter:
"In the Name of God, the Compassionate, the Merciful (1) A(lif), L(am), M(eem). (2) That is the book! there is no doubt therein; a guide to the pious, (3) who believe in the unseen, and are steadfast in prayer, and of what we have given them expend in alms; (4) who believe in what is revealed to thee, and what was revealed before thee, and of the hereafter they are sure. (5) These are in guidance from their Lord, and these are the prosperous."
The Heifer 2:1-5
Alif, Lam, Meem are the three Arabic letters A, L and M (pronounced - written, based on the the revelation, as letters).
Original revealed text:
I will be around, with God's will.