Depicting Naziism through Nazi Swatiskas tends to be offensive to people, even if it's depicting them in an evil way. (Personally I only take offense when it's depicted as something the protagonist of a story is suppose to wear, like the "Daughters of War" mod on the Skyrim Nexus)
It's like we're supposed to pretend that Nazis never existed.
Then again, look at how many parents get bent out of shape when the villain of a story doesn't conform to Christian standards.
And they say liberals are easy to offend.