At the risk of sounding like a hard-line conservative, I would be just as happy if livejournal said no pictures of naked breasts in any form were allowed at all.
I'm not for shoving nursing mothers into closets to breastfeed, but I fail to understand how restricting breastfeeding images (and only as the default icon) in any way restrict the right to breastfeed.
I'm getting a little tired of the entitlement attitude that says it's okay for MEEEEEE to do whatever the hell I want, with no thought for the not unreasonable sentiments of others. Breastfeeding is an intimate act between mother and child. To me, a picture of that intimate a nature is simply inappropriate. It makes me feel like I'm intruding on something special and sacred and I don't like feeling that way. But my feelings are, of course, less important than their right to shove their boobs in my face. Bah.
Of course, having said that, I was thinking I should get rid of my topless Kapler picture, but of course, it's not my default icon, so it's okay.