Wasn't Hitler in favor of animal rights?
Contrary to myth, Hitler wasn't a vegetarian. Although the Nazis purported to pass an anti-vivisection bill, they did not. In fact, they were required by law to first perform their experiments on animals before carrying them out on humans. Experiments on humans did not replace animal experiments; on the contrary, animal experiments made them possible. John Vyvyan, in The Dark Face of Science, summed it up this way: "The experiments made on prisoners were many and diverse, but they had one thing in common: All were in continuation of or complementary to experiments on animals. In every instance, this antecedent scientific literature is mentioned in the evidence; and at Buchenwald and Auschwitz concentration camps, human and animal experiments were carried out simultaneously as parts of a single programme."
However, even if this weren't the case, the merits of an idea cannot be determined by the character of its proponents. If Hitler believed in the theory of relativity, does that mean we should not believe in it? What if Gandhi also believed in the theory of relativity—how would we reconcile the two? An idea must be judged on its own merits.