Since people know that God exists, what religion should they follow? The weakness of people in thinking intelligently is something that blocks their understanding of believing in the Bible, and the God of the Bible. 2 Corinthians 4:4:
The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel that displays the glory of Christ, who is the image of God.
This is why those of us who have been blessed enough to know the truth, need to tell those who have not been blessed that much. But many people reject, even when they hear. If they reject, let them, and go to others, some of which will not reject.
This is the question: "Which religion should they follow?" Yes, here lies the problem that makes many people not believe and prefer to remain irreligious, in which God and in which religion should I believe? God of Buddhists, God of Hindus, God of Jews, God of Christians, or God of Islam?
As for your saying:
The weakness of people in thinking intelligently is something that blocks their understanding of believing in the Bible, and the God of the Bible.
This is a statement that I disagree with, as do the millions or billions of others who do not believe in the Bible.
Muslims, Jews, Buddhists, or Hindus can say exactly the same thing, too.
Is mathematics logical? Someone who doesn't know much about math, might be tempted to say that most of math is silly.
But when that same person studies math and the things that can be done through math, he suddenly finds that math isn't so silly as he formerly thought.
Same with religion. Study the history of each religion, and see what you come up with. For example:
1. The Hebrew people have in the Bible some of the best laws for living life free and equitably;
2. The Hebrew people have passed their Scriptures down from parents to children for 3500 years... the historical time of the nation of Israel since Moses;
3. The Old Testament as a history shows over and over how not following God and His law caused trouble for the people of Israel, and how God saved them when they started to follow Him again;
4. The New Testament was copied around 25,000 times in the first and second centuries after Jesus birth. Why? Because Jesus was powerful, and the people kept the memory of this power;
5. The Bible is the most printed and sold book by far, not by accident, but because there is power in it.
In other words, when you start to examine the Bible, the info in it, the history of the nation that 'wrote' the Bible, and a lot of things about the whole history surrounding the nation of Israel outside of it, you will find that the Bible is an impossible-to-have-been-written book. God is in the Bible.
There is no other nation, and no other book that has a history anywhere near as strong as Israel and the Bible. People don't believe the Bible because they haven't looked. However, for those who have looked and still don't believed... God has given people free will... free will that is strong enough to resist even Him, His Holy Spirit working in them.