My next to last post in that thread said that he did in fact have very liberal views and that he stated them in the last ten years, when social media was firmly in place. And as I said there, I had to hit google to learn that, which meant he wasn't shoving his views down peoples throats, via social media or otherwise.
Nor did his later views seem to get picked up by the social media machine on either side, which likely meant he wasn't giving his views in an inflammatory manner, which was likely the case in the 50s as well, when people seemed a bit better behaved in general, whatever their political persuasion.