It's no hoax, it works just fine, as people who've made the goggles can attest. (It's very interesting how angry this stuff makes some people.)

And yes, if we define the word "infrared" as meaning "invisible light," then if humans CAN see it, it must not be infrared. Bt that argument is more politics than sicence. The real question is about whether we can see 750nM or 800nM or 850nM light. Textbooks call this "near infrared," and your retina just barely picks it up. The farther out in wavelength, the worse your sensitivity, and the brighter the light must be in order to see anything.

If you try making these goggles, a single layer of congo blue will give results which resemble red light. If you want to see frosty pink trees and a black sky, you need at least three layers; seven is better. And you nee a bright summer day.

I've heard claims that the human retina can see 950nM light just fine if the human is looking into the output of an infrared laser. I haven't tried it myself!