I'm not going to pay for the article, but note there's a big difference between sticking this device on a guy and him having to learn how to use it deliberately

I'm not going to pay for the article, but note there's a big difference between sticking this device on a guy and him having to learn how to use it deliberately, versus sticking something on your head and reading your internal monologue. This is almost certainly something the man had to do with great deliberation and effort, not something that was magically reading his mind. I'm not convinced a device to read your internal monologue from the outside is even possible, or if it is, it may be very, very large. A device that sees you're conducting one, perhaps, but reading out the contents externally? I'm not sure it could gather enough information and training data to ever decode it. (That is, my point is more information theoretic than technological.)