"ignorance plus marketing"
I do see what you say - I would say that this is the generally accepted common sense view.
Still, I am skeptic. This means I don't trust what I am told - I only accept as knowledge that which I verify myself.
So here, with food, I get an opportunity to verify what I eat etc - it is anecdotal - but anecdotal is king for me. So, in my anecdotal experience, terrain is at least plausible.
On the other hand, asking me to believe in viruses (that I cannot see) is a bigger ask. I do believe in fungi and bacteria - I can see something of these, but I have never seen a virus.
I am being genuine and honest with you - I really am an (extreme) skeptic. Why should I change my mind and start believing in something I cannot see. I know people lie (often unintentionally) and I know that corporations seek to make profit from people's ignorance - the pharmaceutical industry is no exception. They are all about making money - like every other corporation.
The problem I have is that people are expected to believe corporate information that cannot be verified, over their own personal experience that can be verified.
Do you see my problem? That as far as I can tell, it is pharmaceuticals that would seek to exploit people's ignorance with marketing? No doubt organic food producers are doing the same, but their marketing budget will be tiny in comparison to the heft of big pharma.