Granted that a lot of that early RocknRoll stuff was a bit, erm, questionable (didn't Chuck Berry actually get convicted of doing something with a girl in her mid-teens? - whilst Jerry Lee Lewis notably didn't IIRC), and pretty much anything by Glitter is a no-no, I can't help feeling we're getting a bit squeamish around these parts. I always thought that offensive and/or explicit lyrics were a perfectly acceptable part of the rock business - I played in a function band that did a lot of corporate and wedding gigs. We had 'Teenage Dirtbag' in our set for ages, and audiences loved it. We never, ever got a single complaint about it. Part of it is knowing what the audience is likely to tolerate of course, but even so....
If you took away all the songs with offensive lyrics just because they had offensive lyrics, most adolescents of the last 50 years would have had nothing to listen to at all!