I see nothing wrong with breast feeding even in public, there is nothing sexual about it. However, sensationalizing it like this is ridiculous. I have wondered, historically, at what age children were weaned from breast feeding. I would assume that children would be weaned when they were capable of eating real food, which they obviously can at 3. What age do tribal people wean? Does anybody know?
Average age of weaning in "traditional" societies is commonly claimed to be 4-5. But the range is enormous.
A lactating woman is considerably less likely to become pregnant, so breastfeeding is to some extent a natural contraceptive or way of spacing children.