You must not have children, then. I try to expose my children to bits of everything and my young son has access to the iPhone and iTouch - yes, he could access objectionable content, but Apple should figure-out a way to allow or disallow users based on settings from downloading that content - like iTunes and a rating system. Arbitrary? Yes - but so what if children are exposed to vile and objectionable content on a daily basis? It is best to talk with your children and TRY to keep those things you feel objectionable out of their hands...you can only do what you as a parent can do and you cannot control everything.
As a parent you cannot ALWAYS remove temptation form a child but to make it more difficult and to speak with your child is always better than doing nothing at all. Just my opinion - talk with your children, work with your children, expose them to culture of all types and take responsibility to what your children consume - and I think Apple should make that job easier for parents by instituting a parental control lock on the app store. I cannot and will not sit by my child at all hours of the day to make sure my children to do go someplace they should not...that is why Apple included a parental control feature in OS X. Why not on the iPhone or iTouch? This would then be a moot point, right?
D
Granted parental controls are a nice feature, but the responsibility rests ultimately with the parents - not Apple, not wal-mart, and not Google.
The default position should never be to censor.