Also, being ignorant and being religious has no direct linkages. It's a personal preference. I personally know many scientists, IIT toppers etc who are super religious yet they are steeped into modernity. This concept of "culture" grounds you and makes you humble. It morally binds you to a purpose. Hence, whoever says that the concept of religion is archaic and those who are religious are "gavar" is gravely mistaken. I would say HE is ignorant!!
Having a faith and being religious are two different things. Faith is a personal conviction and is not bound by external factors. You can for instance believe that Spongebob Squarepants is the only true god, but your morality is still your own and based on your own conscience and not dictated by others. Good or bad, its your own decisions to make.
Religion is a group behavior and groups are not intelligent. You blindly believe something without using your own brain because somebody else believes in it. You believe that lord Vishnu is a truly powerful god if your parents are Hindu and go to various temples and give offerings to idols of Vishnu, but if your parents had converted to Christianity or Islam before you were born, you would grow up believing that Yawweh is the true god and that Vishnu is a non existent god who is worshiped by heathens and that their acts are sinful. Some prehistoric books becomes your guide of morality and you try to abide by it without understanding it. Also, most of the time, because of the nature of groups and group mentality, the good bits in religious writings gets discarded over time and only the bad remains.
Religious people almost always have very little understanding of their own beliefs, or the the books they base it on. This was even proved though a test. A number of religious people belonging to various faiths and some irreligious people were brought together and given questionnaires designed to test knowledge on the holy books of various religions. The test was designed access the depth and breath of knowledge and result was that the the religious people knew very little of what is written in their own holy books while atheists have better knowledge of every religious book than the people who proclaim to be devout followers of those religions..
Its not that religious people are ignorant. Its more like religion demands you to remain ignorant and blindly follow something. Why is it that Brahmans controlled all religious books and knowledge of Hindus for eons rather than letting all people have access to them. Why is that Roman Catholic Church controlled the Bible? For nearly a thousand years, procession of a bible by any anybody except the clergy of the Catholic Church entitled them to death sentence. translating the bible was also a capital offense. Same goes for Quran as well. Ignorance is a prerequisite for Religion.
Humans claim to be superior to other animal species, but what sets them apart? its humans individuality and ability to think for themselves even while being part of a society. If humans blindly follow a group just because they were born into that group, then they are no better than a herd of animals that do the same thing.
Regarding your claim of many scientists being religious, any scientist who does not question the concept of god and accepts it blindly is no scientist at all. Doesn't really matter what their contributions are. The basic tenet of science is to question everything and base things on logic and reasoning. Blind faith without evidence has no place in science. I know there are quite a few personalities that made controversial statements, but such statements come out of arrogance than humility. Because they cannot explain something with their present knowledge and intelligence, they refuse to believe that its a simple concept that can be explained away by somebody else in future. They would rather declare that some supernatural entity is behind it than accept that there their current understanding is limited.
As for "IIT Toppers" please don't make me laugh. IIT topper is not some sort qualification. All you need to get through IIT entrance tests is repetitive practice and these days, even those tests have been dumbed down considerably. I have seen a lot of dumb people in IIT's (during education and at work) without basic understanding of the concepts that they were supposed to understand and be able to apply. There are lot of people who manage to enter without even a basic scientific temper leave alone a knack for engineering or interest in the subject they are trying to study there.