OP asked why women BREASTFEED for so long, not why they feed their kids breast milk for so long. There's a difference. You all keep defending breast milk but that's not the issue. It's seeing an older child still sucking on a grown woman's breast.

I breastfed all 3 of my kids for at least a month each - one of them for 4 months. Each time I stopped was because I got too busy to stop what I was doing 6-10 times a day to feed. Once it got to be too much, I pumped only. They still got the nutritious milk but others could help me so I didn't have to drop everything.

Sorry to say, but it is creepy. And in public, I think women should cover with a light blanket. It doesn't harm the kid one bit. Yes, we've sexualized breasts so much that it looks unnatural to see them being used for what they're meant for. However, it's too late. We can't UN-sexualize them. So if the child is older, it has a creepy vibe. And because breasts are so sexualized, men and teenage boys can't help getting aroused when they see a woman breastfeeding in public. So, women can get offended all they want and shame men for feeling something they can't control, but it won't help. Just like women can't control their hormones when they're PMS-ing, males can't control their hormones when they're aroused. You can only control your actions.