Yes, the " twisted cross " is a VERY ancient Indian ( India, as in Hindu, as well as American Indian ) symbol. This IS common knowledge ! It's amazing that you do not know this.
Well, its not that common. I assure you of that. There are many people who do not know this.
The article is a pastiche of rather uncommon things, cobbled together, to prove that they ado indeed have a commonality. You didn't understand it, as well as you imagine you did. This article IS base propaganda !
Well, all I can tell you, is that most people DO know the history of " the twisted cross " ; at least in the USA and probably in England and in India.