Well, think of Madonna when she released "Material Girl." How would she be considered by someone being 30 years old in the 1950s? Much worse than what you consider Britney Spears today, I believe. I completely understand what yuou're saying, but I think that, simply, the perception of what is acceptable or non-acceptable changes over time. I would not worry for our supposed 10 year old children, since I don't think they would be negatively influenced by Britney. On the contrary, they will not see in her anything more shocking than what you (and I, ok, I admit ) used to see in Madonna 15 yrs ago, and will laugh at you and me the same way we may laugh at our parents and their "puritanism" of the 50s or 60s... :)
Overall, I think we're getting rid of superficial formalities, in a way, and that's not necessarily bad.