Gnosticism is another jewish program.

Why Hitler Destroyed Freemasonry

Many were, yes, but not all:

https://satanisgod.org/ABRAXAS_GNOSTICS.html

he received information that's definitely. but from who that's what you can't be sure about.
i think you shouldn't bother about it! neither his spiritual allegiance and just take what makes sense, helpful for you or solving any mysteries!
here's a statement by High Priestess Pythia about the book (Cloak of the Illuminati):
"Although this book has a lot of valuable information if one reads between the lines, the author is deluded as he believes in the fictitious nazarene."
it's fine to search for the truth everywhere, with working your mind out and holding on our path you won't be deceived.