What should I have done in this god awful situation

OK so this thing that happened to me two years ago popped up in my Facebook memories today and just made me think of it again and I wanted to come on here and ask what would y’all have done in the situation.

So two years ago today I was walking around Walmart with my daughter in the cart she was mad at me because she didn’t want to get a toy and I wouldn’t let her get a toy. As we were walking up and down the aisles we heard a woman yelling at the top of her lungs at her husband calling him names and putting him down. Now I always try to stay away from situations like that but Unfortunately I needed something on that aisle and I had to get to a doctors apt so I was just gonna real quick jolt down the aisle grab what I needed and leave. As I turn the corner and come into the aisle I see the couple that’s arguing it’s an average sized man and his wife was a little person. I only mention that because it pertains to the story. She’s just steadily calling him a pussy saying he doesn’t have the balls to stand up to her yada yada. I felt bad for the guy. All of a sudden my daughter glares at me and said “she’s mad that her daddy won’t let her get a toy too” loud as hell

Now mind you my daughter was 2-3 at the time and we don’t know any little people so she didn’t understand and as I said she was ticked she couldn’t get a toy. She sees this little woman yelling and stomping at this grown man so in her head that’s how she saw it.

This woman just evil eyes the hell out of me and my daughter and I go “Ma’am I am so sorry” and she interrupts me and goes “really bitch you need be an actual parent and educate your child about people with disabilities so she doesn’t offend anyone else!” At this time her husband is trying not to laugh I’m sitting there dungfounded and she is PISSED. I tell her again “I am so truly sorry, we don’t know any little people so we’ve never had to have that talk with her” and she keeps drilling me until I apologize again and leave. What should I have done. Ive since had many talks with our daughter about it but I mean did I react badly should I have done something else