Seems to me that a lack of patience is part of the problem. Some people would like to be able to really understand why special relativity is true and go through the argument and experiments but they'd have to invest quite some time doing so, before they'd find out for themselves. So too various other things people would like to know, but believe they haven't got the time to deeply examine. Couple that with a compressed curriculum in education where students now need to know more than ever before and know it in less time. Couple that with our society that puts information into increasingly small packets, that spends vast amounts of advertising dollars on convincing people in the shortest optimum time to buy some item, and it's revealed that people are time poor when it comes to deeply understanding and investigating what it is they want to know.

Now with regards to "we still don't even know what kind of food is best to eat!" That is a question that we do know! But you probably won't find it in advertising material, you probably won't find it one particular book, and you most certainly won't find it in one particular eatery/restaurant. You will find the answer from a professional dietician/nutritionist (whatever your country calls them) that's spent about 3 years studying to find out the answer in all its complexity. Shall we trust that professional, shall we have faith in that professional? Or do we want to find out the answer for ourselves... whilst we struggle with paying the mortgage, getting the kids to school and meeting our work commitments?

When we dismiss "faith" and "trust", and I don't mean in a deity, I mean when we dismiss faith and trust in other humans, we are left in a very precarious position of having to work it all out for ourselves.