My first drive by

There is a phenomenon that I have learned about since becoming a mother called the "mommy drive by." The idea is that someone who doesn't know you, or know anything about you or your kids, criticizes your parenting skills out of no where. I had my first one today.

There's an older woman who is retired from work but still goes to the gym (I haven't quite figured out what she does there besides use up about 25 towels, but that's her prerogative). Today I was changing next to her and we started chatting. She wondered what I did at the school, how long I had been there, etc. etc. She made some comment about how she was old enough to be my mother which always irks me so I told her my age which led her to ask if I had kids, and then ask how old they are. She asked me if I was still breastfeeding and when I told her that I weaned Chava around 8 months, she launched in to a diatribe about how jobs come and go but the benefits of breastfeeding last forever and I should really go back to breastfeeding. She even asked me why I stopped - I should have told her it was none of her business but instead I stupidly started to explain what a challenge it was to pump, which she immediately poo poo'd. I just sort of nodded and packed up my stuff and left, feeling like crap.

Why do people do that?