Maybe it's "Holocaust fatigue?"
With all the pogroms, and persecution the jews have endured they have rightfully been diligent in trying to make sure it will never happen again. When I was in high school i had to read he Diary of Anne Frank, we watched Schindlers List, our history class when it touched on WW2 focused heavily on the shoah.
But as with slavery with Black people, some might find the whole narrative tiresome. The backlash may stem from bigotry, or maybe the fact that people just want to move on.
Others reasons may be that some think that the leadership in isreal uses the holocaust to justify their ongoing subjugation of the Palestinian people and the theft of their lands.
Some also point out that many other people like the Russians, and Chinese also experienced horrors that exceeded that which were inflicted on the jews, but the jews have been more organized in maintaining their victim narrative.
And then again it could be just good ol' fashioned bigotry that is enabled by the anonymity that the internet provides.