What is an offensive breast?

I enjoyed reading this post about how showing a breast being used to feed a baby is considered obscene, but using it to sell a product is not. I wanted to add that usually the non-offensive breasts are on waif-thin, Photoshop-retouched models. And that usually you don't see the nipple (although of course you don't usually see the nipple while a woman is breastfeeding, unless her baby pops off to take a peek around). The magazines aren't usually the same type, however. Parents or Baby Talk or whatever are targeted at mothers -- so you'd think showing a breast doing what it was made to do, feed a baby, wouldn't be that big a deal.
If you are in San Francisco, you can show your breasts in public as long as your nipples are not exposed (you can put bandaids on them, or electrical tape, and be legal because you are concealing that they are in fact breasts not just round blobs). I know from experience, you might say. Anyway, all this is to say that humans are trying to deny that we are mammals, and that women's breasts are made to feed babies, and that babies are meant to drink from them. We aren't birds, for goodness sake! Actually, even pigeons and many other birds feed their babies with food they first consume, at least. Not taking milk from another species and processing it until it's an imitation of the real thing.
Maybe humans are trying to create a new offshoot of the mammal order (or whatever the grouping is called)? Maybe there will be a new species that no longer bears live young, breastfeeds, or has hair? It will be used exclusively for pornography, modeling, and other aesthetic uses. They can all live in cities and live in condos.
Brilliant!