I understand what you are getting at here, but I have to disagree. My view is that state sanctioned intolerance is usually a top-down process, primarily driven by economic incentives.
Hitler for example exploited the absolutely dire economic situation of Weimar Germany, directed the hate against a clearly delineated social group who were perceived as wealthy.
Same thing in Uganda, Kosovo, Rwanda etc.
People switch from being tolerant to intolerant in an instant (with tragic consequences) but it is almost always driven from the top.