"...the attempt to make heaven on earth invariably produces hell."  –Karl Popper

Noam Chomsky and Malcolm Caldwell had a lot in common:  Both despised the USA, both were men of the left, and both denied that the Khmer Rouge were bloodthirsty monsters even after it lay gorged on millions of victims.

Now that a few decades have passed, just about no one would defend their record here.  It's worth reflecting on how little the left can perceive in the arena of leftwing evil:  Leftwing regimes kill the most people of any, and they are precisely the blind spot of leftwing intellectuals.  It's also worth noting that when someone denies the Holocaust, their reputation takes a big hit.  But not, evidently, when someone denies Communist mass murders.

If we are uncritical we shall always find what we want: we shall look for, and find, confirmations, and we shall look away from, and not see, whatever might be dangerous to our pet theories.  –Karl Popper

https://chomsky.info/19770625/

https://www.theguardian.com/lifeandstyle/2010/jan/10/malcolm-caldwell-pol-pot-murder