It depends on what art your pushing though. I think art can be absolutely disgusting and shouldn't be shown to children. The fact is overall though, you can't tell someone what to do with their art. Its freedom of speech, unless it hurts another person. Its not right in that case.
Everyone who creates art has right to create whatever they want and to express themselves. Though there are should be regulations set in place to control where they can display or publish the inapproriate artwork. Mainly to protect young children from seeing art that is not approriate for them to view.
This is why I never understood censorship in the United States. Why do we have to censor anything. It's there. It exists. Not only does this infringe on the rights described in the first amendment, but it's silly and childish at the same time. Pretending something isn't there doesn't stop it from existing.
Yes, First Amendment rights include the ability to express yourself through art. Censoring someone's art is indeed an infringement of their First Amendment rights. But let's make sure we're also clear that is only the case when it's the government doing the censoring. Private galleries and individuals can do what they wish.
Art censorship does not infringe on our rights under the First Amendment. The First Amendment guarantees freedom of speech, but says nothing about guaranteeing that people have the right to display any type of art they choose to. I know that some will say that their art is a type of expression, but it would still not fall under the First Amendment.