That pretty much sums it up. Even with shows that are aimed at a more mature crowd such as Family Guy, South Park and Archer there are still ignorant people that instantly assume that if something is animated that it's for kids.
TV Tropes refers to this as the Animation Age Ghetto.
It's also the main reason why if you manage to find the rare beast that is a Blockbuster Video/local library that actually has anime that you'll usually find the likes of Bleach and Akira right next to Disney films in the kids section :-/