DVG, I hardly think that Josef Mengele is the best representative for the world of science. Nor is Osama bin Laden the best of the religious camp. Abstractly speaking, there is nothing inherently evil about science, which is, simply put, a methodology for investigating the natural world. Call it belief with evidence. Religion, however, calls for belief without evidence, which can lead to all manner of mischief.
What propelled Mengele to commit his ghastly atrocities was his belief in the racist ideology of Nazism--talk about belief without evidence! Then again, he may have simply used that ideology as a justification for satisfying his sadistic impulses. In any event, there's no doubt that many Germans accepted the whole "master race" bullshit, and if some employed "scientific" research to "prove" it, I hardly think that such constitutes an indictment of science.
Science is an investigative tool, and, like any tool, it may be used for purposes either constructive or destructive. Conversely, while it is true that religion may inspire people to do good deeds, I would challenge defenders of the faith to show where, over the past five centuries, faith has produced the advancement in human knowledge and the betterment of the human condition which science has. Science and technology have, in the medical field alone, brought about amazing advances that have saved countless lives.
In a sense, the 9/11 attacks coupled the worst of religion (Islamofascist terrorists) with the best of science and technology (jet airplanes). But the planes were morally neutral in that equation, as is science; it was the hijackers, inspired by their idiotic religious beliefs, who were evil.
Rather than nominating Mengele as being representative of scientists, I would nominate Carl Sagan or Isaac Asimov or Stephen J. Gould or Richard Dawkins. Yes, there are bad apples in every barrel; however, the scientific barrel is not spoiled by the few despicable Mengeles found in it.