So to clarify: you seem to think it is better to be a poor role model for young women by showing them that being a woman is about how skimpily you dress and how sexy you can be; than putting some Lord of the Rings etc in your songs.
Many of these bands do it as a gimmick, nothing more. What specifically do you find offensive about Led Zep? I would have thought you'd be ten times more offended by the sexual nature of the lyrics. Again, though, I don't see it as anything other than fun. My husband and I like Led Zeppelin's music and we have a laugh at some of the puerile lyrics in songs like "Whole Lotta Love." From that era, though, you can find all kinds of sexual content in songs. In my eyes it's boys trying to show off, nothing more.
I have a friend who knew some of the members of Led Zeppelin in their early days, before they were famous. He was a newspaper reporter in their city. They're not dangerous Satanists, they're ordinary people who wanted to be noticed. They've actually managed to stay ordinary in ways that many famous people don't achieve.
By the way, listening to those songs does not encourage me to do anything other than appreciate their artistry. They rock.