Laughing at others falling down is one of the simplest joys in life. Does it make you a dick for laughing? Err... yeah, probably.
So, of course watching a Disney character fall down because of their bulbous head is going to be an enjoyable experience. Just try to ignore that part of your conscience that wants you to feel bad because there's a person inside that Goofy costume. (Your conscience is always a buzzkill anyways.)
Side note: how about that part at the end where Elastigirl's face falls off?! Some kids were definitely scarred for life that day.