I was exposed to more conspiracy theories in my youth (80s-90s) than today, and like today, scientists were trusted as long as they didn't put your preconceived ideas into question.
The difference is that conspiracy theories used to spread undercover. So you may not know about them all, but when they reach you, they are more convincing, as if you were given access to secret knowledge, and also, debunking was more difficult. Now they are for everyone to see, but it doesn't mean people believe them, especially considering that the debunking is just as assessible.
I think it is what I would call the "people are idiots" fallacy. You always assume you are smarter than "people". Because you are smart, you don't believe in whatever bullshit there is on the internet, but "people" are dumb, so they must believe it the second they get exposed to it, and in some cases, they do, but there is often more than stupidity. But I think that generally, people are smart, and except for a minority, if you can tell obvious bullshit, so can them. As for non-obvious bullshit, it is true people sometimes fall for it but so do you and me, but I don't think that's what the author means by "tinfoil theories".