The theory being that other women breastfeeding implies that it's a good time to have kids, that the environment is suitable.
To me, the fact that most women in America don't breastfeed gets at the root of two things people don't like to talk about in America: class, and sexuality.
Class: I'm sorry, I forgot, everyone in America is middle class. Some upper middle class, some lower middle class. Bill "I'm not a monopolist, really" Gates is upper middle class. What was I thinking? Seriously though, we are so unwilling to address the class issue it's not even funny. Anyone even bringing it up is immediately accused of being divise, or un-American, or some damn thing.
Breast feeding is not seen as something prestigious to do. It's just not upwardly mobile enough. Even in the UK, where they are less uptight about nudity, at least, they don't show it very often on TV.
Sexuality: The article mentions that the woman doing the breastfeeding often enjoys it. This has been shown in studies for a while: what's new is that other women benefit too. A lot of people, including women, can't handle the concept that women can enjoy breastfeeding. (I also realize some women don't enjoy it.)
For the "old school" Puritians, it's just your basic suspicion of pleasure. But I get the feeling that some breastfeeding advocates want to avoid this issue entirely and focus just on the health benefits. It's like the Puritians say, any touch/nudity is sexual and sex is bad, and the neo-Puritans say, it's not sexual, it's only because you're a sex-obsessed Puritan that you would think that.
Why can't it be about sex, among other things, and be good? Lord knows that mothers have a high enough stress level. Why is bonding supposed to happen without pleasure somehow?