Boomer thinks it's okay to touch my child, and doubles down

Today, my 2yo son and I were waiting for our order at Costco's food court. He was sitting in the child seat of the cart, leaning over, hugging a balloon. Enter Boomer Lady. She comes over and begins touching his back and trying to talk to him. Immediately, I sternly told her, "Excuse me, please don't touch my child." She seemed taken aback and mentioned he reminded her of her granddaughter. I reiterated, "Okay, but it's not okay to touch someone's child. Please don't touch him. I'm very protective."

We collected our food and sat down to eat. A little while later, the woman approached us again. She said, "I'm sorry for touching your child, but I don't know what country you're from, you didn't need to be so rude to me."

I was ready to accept her apology... but nope, she doubled down!! AND added xenophobia to it! I snapped back at her, "I don't know what country you're from where you think it's okay to touch someone's child!"

"I'm from HERE! I'M FROM HERE!" she said, indignant that I could assume otherwise.

"Well you still shouldn't touch someone's child!" I responded again.

With the most boomer of retorts, she spat out "You're STUPID," and started storming away.

Something in me had to have the last word, so I shouted after her, "I was polite! I said EXCUSE ME, and PLEASE don't touch my child!" She again threw another "You're stupid!" over her shoulder as she stomped off.

Thankfully some OTHER boomers sitting nearby were polite and started chatting with me and asked what happened. When I told them, the fully backed me up, agreeing that was inappropriate behavior from her. I hope she goes home and bitches about me to her boomer friends and they also put her in her place.