Does Stallman wear a Che t-shirt under his exoshirt?
I doubt it. I certainly would hope that Stallman is bright enough to realize that Che and freedom are polar opposites.
As far as I can tell, Stallman's political beliefs are personal and are not part of his public image at all. I would be quite disappointed if he mixed politics into his beliefs about free software.
If you have an authoritative source (like cited quotes from Stallman) that indicates otherwise, please pass it on.