People are responsible for their own actions. "Hitler told me to" or "David Icke told me to" do not excuse anything someone does. I believe we established particularly after WWII that "I was just following orders" is not a valid defense to committing atrocities.

You might also want to remember that one of the first things Hitler did after getting power was to outlaw any opposition parties and violently break up meetings of any dissenters, then arrest and torture anyone who was promoting anything other than the Nazi party line. Hmm, sound familiar?