I am very thankful I live in a place that protects the rights of women and allows them to breastfeed in public legally - unfortunately not without some judgement, since nursing is resurging in popularity but still not the norm.
The other day I was at an event and the woman I was talking to nursed her 2 year old. We talked for a good 20 minutes. As I was leaving, a guy I know walked up to me and asked, "Was that lady breastfeeding?" And I said frankly, "Yes, she was. It's no big deal." And he saw the facial expression I had and seemed to understand. He didn't know if it was normal or not because it was not something he had seen a lot, or been exposed to. And he wasn't sure how to react. "Is this lady doing something acceptable? Should we allow her this right? Should I say something?" are probably some of the things he was thinking about, but couldn't come up with answers with until he saw how nonchalantly I answered his question. He probably then thought: "Yes, this is normal. It's acceptable. It's her right."
People who do not get to see positive models of motherhood - like nursing and tending to babies in a way that is not "private and secretive" have some weird ideas about breastfeeding. That it's weird, sexual, creepy, perverse, inappropriate, dirty, etc. I think this is mainly due to lack of exposure. People are afraid of what they do not understand. And when they feel some fear about what they are viewing (women nursing) they rationize their fear by making up silly excuses that only work superficially if not at all.
It is very sad that you do not understand breastfeeding but it is even more sad that you will likely at some point in your life shame a woman who is breastfeeding or wants to breastfeed - whether it is the mother of your children, a relative or a stranger in public. And shame on you for that.