"Scientific authority" is the source of the genocides of the 20th century, mass sterilization, what we now consider crackpot science, and many social ills. I would say it is actually worse than the religious authority of the past.
"x authority" has been a large source of problems all through human history. Insert religious, ethical, scientific, political, etc, etc. Biggest problem with science is that it has enabled excesses for those in power (be it authoritarian, communist, capitalist, whatever), while somehow remaining meek and pretending to be amoral. It is easy to take the benefits of Science without bothering to learn what it has to say about anything else.
Saying "the Nazis had doctors, therefore the lawn signs today are actually worse than religious atrocities of the past" is an equally unconvincing argument.