I do think there's a big question about it when the head of this Un-American Activities committee is currently on the payroll of the Soviet Union while talking about a plot orchestrated by capitalists, yes. That doesn't mean there wasn't one at all. What that does mean is that the Soviet spy angle has some questions on how it was presented (as in reality if they really did approach Smedley Butler, one of the very few socialists in the US High Command they were dipshits who deserved to fail).