Aeismail’s answer is spot on: who you choose to dedicate it to is entirely up to you (modulo political expedience). I've read theses dedicated to martyrs and I've read theses dedicated to cats. Do what you feel moved to do. See answers here for some discussion.

As for how it would be received by the Jewish community and Jewish mathematicians, I am confident that the answer is "extremely well," based on my experiences and conversations about similar tributes. On a personal level, as a Jewish mathematician and descendant of survivors I would find this incredibly meaningful to come across and quite likely be moved to tears by a well-written dedication along these lines.

A tip about writing the dedication: one common mistake that people writing about the Holocaust make is to paint it as “unimaginable” or “unprecedented.” Although it is by far the single largest genocide in terms of total number of people killed (6M Jews, 5M others includes Poles, the disabled, and homosexuals) that usually rubs me the wrong way. The Holocaust is without a doubt the most socially prominent, but definitely not only, example of persecutions of Jews or of genocide as a whole. It’s also not the most recent or “last” (I see people use this term) genocide, nor has Nazism gone away. Today there is genocide in Myanmar against the Rohingya people and in Iraq against the Yazidi. Today neo-Nazis openly march in Virginia, USA while targeting Jews in their chants and waving the swastika. These facts are things people tend to be unaware of, and so people can sometimes accidentally take away from their tributes through inaccurate or dismissive words.

I think a dedication to Tauber and the others who were murdered would be lovely, but caution you to think carefully about the wording lest you accidentally minimize or dismiss the aforementioned facts.

A couple of people seem to have missed the fact that there’s a direct connection between Tauber and your work. To explicitly state that for anyone who is reading this: the field that is the topic of the dissertation is known as “Tauber Theory” and (presumably) Tauber’s work was foundational and central to the field and the dissertation.

Who you choose to recognize in your acknowledgments is up to you. If you would like to dedicate it to the memory of someone, that's entirely your choice. If you are worried about the political backlash, you could submit the thesis to the reviewer without the dedication and acknowledgments and then add those at the end.

a mathematics thesis might not be the place to "confront" like this.

No, I disagree. There are few ways in academia to draw attention to this crime more powerful than the acknowledgements section of your thesis. I hope you choose to do so!

Also, to speak to another part of your comment . . .

I am a Muslim student in a non-Arab country. Would it be unwanted/inappropriate for me . . . .

That you are Muslim does not detract from this in any way. Politically, to the Jewish communities, that you are Muslim would only add more power to your acknowledgement.