I don't know how credible this particular hypothesis is. However, I find it distasteful. I feel the same way when someone snickers that the terrorist who crashed an airplane into a building is a "coward" or the right wing preacher who derides gay marriage must secretly be gay, or the rich *censored* in the Porsche must have a small penis. All different examples, but all examples of self-delusion and frankly a type of rhetorical cowardice commonplace.
Maybe Hitler had a micropenis or maybe he didn't. Do you suppose that a man with a normal sexuality would be incapable of perpetrating such evil? If not, who cares if Hitler might have been sexually handicapped? If the preacher who condemns homosexuality is secretly gay, does that make him more evil or less evil than the preacher who condemns homosexuality who happens to be straight? Is the *censored* in the Porsche who nearly runs you off of the crosswalk less of an *censored* if he has a big dick?
In a completely different (but somewhat related) example, I read last week about a kid with allergies who was escorted off an airplane because he was reacting to something on the plane, possibly a dog. The big kerfuffle was that passengers apparently cheered when he left the plane, which his family interpreted as a rude gesture. The mother made sure to mention in her "tweet" that the boy was heading home after visiting his father who had terminal cancer. Every single article just had to mention the cancer. The whole story was how the kid's dad had cancer. Oh boohhh hoo those monsters clapped and the boy's dad had CANCER! On TV whenever I watch Chopped the competitors need to blather on about their nephew with Down's Syndrome or their mother with cancer. S F T U!!!
Sorry for the not completely unrelated tangent.