I don't know the guy, or follow him closely, but I don't think he's dishonest, I just think he's wrong.
There's a distinction between a snake oil salesman and someone who actually believes in what they're selling.
It’s irrelevant if he believes in their efficacy or not. Alternative health practitioners certainly believe in their remedies. Gwenyth Paltow certainly believes in… whatever absurdities she’s peddling nowadays. The Food Babe probably does too. None of that makes them any less snake oil.
Edit: A quick search on Wikipedia shows me I’m wrong. Apparently it’s only snake oil if the seller is aware the product is fraudulent. TIL.
Edit 2: I might not be as wrong as I believed. A snake oil salesman can also be a quack who promotes medical practices based upon ignorance, which would definitely encompass Gwenyth Paltrow and the Food Babe.
You could (accurately, in my opinion) describe the things Kurzweil is selling as "snake oil" but I wouldn't describe him as a "snake oil salesman."
A whole lot of medicine practiced throughout human history has been based on ignorance, but I wouldn't describe medieval doctors (or whichever era) as "snake oil salesmen" because they believed in what they were selling.
This is a pretty important distinction, in my mind.