Events that surround or represent controversy will also draw large crowds irrespective of their intelligence level. Trying to draw the conclusion that the numbers visiting an Evolution display suggest mindlessness as you have done is useless, because your argument in this case is based on incorrect premises.
I find the thought that large crowds are generally drawn to more things which require very little intellect, to be completely wrong...
Large crowds are drawn to all sorts of things...sports events, like baseball, football, basketball, hockey, NASCAR, horseracing.....museums of all sorts draw huge numbers of people...many of the things museums exhibit would appeal to people of great intellect....large crowds are drawn to many of our National Parks, for all that they offer...large crowds are drawn to various churchs for what they offer...one could go on and on, you get the point...
Whether an event, or a place, or an exhibit draws large crowds, cannot be used to indicate how intelligent the people are, who view these things...that is just wrong...my guess would be, that at any event, or place, that draws large crowds, there would be people of the whole wide spectrum of intelligence...frankly, thats the only thing that makes any sense....