@marathon Oh I am not one either for sure. But GPLv3 is definitely not the most restrictive licence from the user's perspective nor it offers high protection for the author of the software (It is actually the opposite!).
I think their tutorials are good and okay to follow along. My guess is that they advocate for open source but not free (libre) software, so they try to disrupt the reader's view about free software. I do hope that I am wrong and they just don't know the details.