How can propaganda become dangerous

Propaganda can become dangerous when People try to utilize values into facts. 

WHAT DOES EUROPE'S WAR MEAN FOR AMERICA? Now and later, this crisis means that America will be flooded with propaganda for war, propaganda for appeasement, propaganda for participation and for non-participation in the issues of Europe. Excited by these propagandas, it is ikely that many of us Americans may lose our heads, throw reason out the window, follow courses of action which we may regret later.

Ireally don't know