The problem they have is not really the fact that a comparison is being made to one of these horrific tragedies; after all, we build museums, memorials and reminders of what happened to make sure something like the Jewish Holocaust will never happen again. The problem really is that we have elevated what they consider to be a blob of tissue to personhood status.
If comparison in and of itself were the problem, then we would not go to such great lengths to educate society about what happened. The reason places like Auschwitz are open for the public is to guarantee that we understand the horror of what took place in the death camps.
This is precisely the reason we use such imagery. We want to the world to understand that what makes us so sick about Jewish Holocaust is precisely what makes us sick about the Abortion Holocaust. We talk about the Dred Scott Supreme Court Decision because we want people to see that Roe v. Wade is just as despicable.
The same reason these people are so upset about pro-lifers using these comparisons is the very reason we use them: personhood.
