Does it really matter whether Hitler had some Jewish ancestor or not? Does it change what the man did? Does it change the devastation and destruction he caused?
Judaism is a religion. Like many religions, it sometimes recognizes members who are rather lapsed in their practice, and even will claim their children as members. But, in the end, it is just a system of beliefs. If everyone who was matrilineally descended from a Jew was actually Jewish, there would be a lot more than the 12 or so million Jews around today.
Until quite recently, no Jewish authority would question anyone who claimed to be Jewish. If you said you were, that was good enough. No one bothered to check birth records. It was simply assumed that if you claimed to be Jewish, you were either insane, a glutton for punishment, or Jewish.
What made being Jewish an ethnicity were those outside of Judaism. To these people, you can’t be Jewish and whatever their ethnicity was. These people made the special laws that kept Jews in their place. They forced Jews to live in certain areas and prevented Jews from holding certain jobs. They made Jews were special clothes and pay special taxes. Hitler merely took the tradition to its logical conclusion.
I am almost 100% German/Austrian by ethnicity. My family can trace their root to Vienna and to Western Germany all the way back to the 14th century before the idea of what was France and what was Germany were firmly established. German Jews, like many Germans were very proud of their German roots. They spoke German, and even had proper German names. Yet, in 1936, these deep German roots would have done nothing to save them.
My Father-in-law’s family lived in Iraq for over 2000 years. His family spoke Iraqi Arabic, dressed like other Iraqis, and participated in their culture. They even had Arabic names. To anyone outside of Iraq, my Father-in-law’s family would be just another Arab Iraqi family. However, to Arab nationalists of the first half of the 20th century, he was not an Iraqi, but a Jew – a foreigner. It didn’t matter that his Iraqi roots probably stretch farther back then any of theirs. He was a Jew. In 1952, his family was forced to flee Iraq, leaving behind all property and possessions.
Ethnicity is a social construct. What made someone Black in the U.S.? That was set by the various state laws, and could be arbitrated in court. Some states even had special courts to determine ethnicity. In Louisiana, it was officially 1/16 Negro blood. If you had that, you better make sure you walked the right way down the sidewalk and didn’t drink from the wrong water fountains. Before 1865, you could even become the legal property of another person. Twain’s story Puddin’ Head Wilson showed how much race was a social construct.
I always get the feeling that this Was Hitler Jewish? question is somehow going to be detrimental to us Jews. You have people like the OP protesting that their Hitler was completely German and thus couldn’t be tainted with Jewish blood – as if those were incompatible. But, what is the other side trying to prove by claiming Hitler had some Jewish ancestry? See, that’s why Hitler was evil! Deep down, he was Jewish!.
Hitler claimed he wasn’t Jewish, and that’s good enough to make him not Jewish. And, as a Jew, I wouldn’t want him anyway. The OP can have him.
Mike Kelly, a columnist for the Austin Statesman, once wrote about a book he read where the author claimed that Jesus had children, and those children became the royalty of Europe. Kelly mused that he could imagine someone tracing his family tree all the way back to Jesus, then getting kicked out of his country club for having Jewish ancestry.