If kids hear swearing and stuff every day, their parents can have a conversation with them about those words. They will be less likely to use them trying to be funny. Free speech exists, and it's being prevented by music censorship laws. If you don't want your kids to hear it, turn off the radio.
Yes, I do think that censorship laws hold back the art industry. If the censorship laws were took down, I bet that a new age of art would boom, and would showcase the art of the body. There would be a lot of very graphic images being created and shown.
No, music censorship laws do not suppress the growth and development of art, because there are good reason to censor some music. For example, many parents do not want their children listening to profane language on the radio. That is fair censorship. Most of the music that is the best does not contain a great deal of lewd or profane content, anyways.
The laws of censorship do not depress the growth of art. In music, censorship is there so that the enormous amount of vulgar lyrics don't fall into children's ears. In art, we don't want to have pornography just posted anywhere in the world. In dance, we certainly don't need to have any more Miley Cyrus's in our culture.
Artists who feel their art is being suppressed because the distribution of that art is suppressed are not in the industry for the art. Art should be something that is created for its sake. Blinding your purpose based on how big of an audience you get is a misguided notion. Popular music is garbage, but validates the egos of the artist based on mass approval. If the reason you want to do art is for popularity, what you really want is popularity. Stop blaming art for your ego.
Music censorship is needed so kids don't listen to music they shouldn't be at such young ages. Censorship laws don't hurt the growth and development of art, it should make things more creative as people can work around such laws to be even more expressive than before. Censorship is bad in general, but sometimes it helps more than it harms.