How can you tell whether I am as trustworthy as a guy on the bus on matters of software engineering? I am a high school dropout. Likewise, I'm no medical doctor, but knowledge is a spectrum, and I believe I know more than the average Joe on matters of nutrition because it is something that fascinates me and I've read and researched a lot about.
Given that I've read and heard about Taubes for 15 years, it is simplistic to say the least that he doesn't know anything because he's got a physics background.
tl;dr: the Gell-Mann effect only makes sense in a vacuum and if you really want to believe that having a degree automatically makes you an expert with worthwhile ideas.
I’m also underqualified for my position and am wary of credentialism. But if I’m looking at a topic I don’t know well — e.g. seismic building codes- I have to start somewhere.
Software engineering is thankfully a field that is particularly accessible to people without formal training. Demand is high, functional skills can be proven on the spot, and employers are (usually) not in a position where their hiring decisions have potential legal consequences.
Titles don't help. An "environmental engineer" might not have sufficient knowledge about zoology or bridges to support whatever they are talking about, but a layperson might not realize that.