They are wrong, of course. Not merely wrong, but anti-American.
Just as these wanna-be arbiters of our diet would point to a donut and claim it is nothing more than dough fried in grease with a lot of sugar, so they would point to another great movie about superheroes, for example, Avengers: Age of Ultron (2015) and claim that this movie has no worthwhile plot, characters, motivations, while it is filled with violence and stupid helicopter-like aircraft carriers. Yes it is true that a donut is made of fried dough with sugar and, on the surface, A:AOU is empty of even the flimsiest justification for its fulsome budget, in reality it speaks to the greatness of the American filmmaking tradition just as the donut speaks to our fine and healthy American traditional cuisine. This does not even need to be defended. Even the most craven of anti-American sentiment can see this is true.
Besides look out in the world. What else would we do with the money, the hundreds of millions of dollars spent on such fine films? Feed the starving in Sudan? Please be serious. Educate our poor and disenfranchised people? Why bother? They are poor and they deserve to be poor. Everyone knows that.