Why do people try to rescue me from the horrors of homeschooling?

What do you say to people who decide on their own accord that you are living your life wrong and you need to change?

The incedent happened on Friday when a cashier asked my daughter if she had fun on her last day of school. MY daughter and I were caught off guard (cause we have learned to lie and just say yes or no) and we stated that she was homeschooled but did have fun today. Then the cashier proceeds to tell me that her child goes to a good private school and that I need to go there and enroll my children. So I try to ward off that comment by saying no thanks, I have two kids and private school is just too expensive. And she replys that they will let me work at the school in exchange for tuition.

Now I am doing my darndest not to insult this woman, but I am also getting pretty steamed that someone is being so forceful and direct about my personal business. How dare she decide that my kids and I would be better off if I stopped teaching them and instead work at a school while they were separated from me and put into classrooms where they belonged? MIND YOUR OWN BUSINESS!!! I screamed in my head while outloud I only said " We are good where we are thanks". She had the nerve to be insulted! THE NERVE!

All she had to say was NOTHING, and mind her own business.