Welch called them "Insiders" and thought their membership transcended race, religion, and other such factors. The Communist movement was but one dimension in their efforts, but not the whole of it. That was the more criminal aspect of the conspiracy, as it also included such groups as the elitist Council on Foreign Relations, the Bildebergs, the Tri-Lateral Commission, and other such organizations whose purpose it was to undermine Americanism and promote internationalism over nationalism.
Anyone who can look at how far we have come down this road since the end of WWII is simply not paying attention.
For a more accurate understanding of Robert Welch, see the new biography about Welch (published this month) that was authored by a PhD historian.
https://press.uchicago.edu/ucp/books/book/chicago/C/bo123795778.html
Your understanding about Welch is deeply flawed. He made massive errors in analysis and judgment despite his “intelligence”. THAT is why almost the entire conservative movement in the U.S. denounced and rejected his views.