How often do you/your kid encounter rude comments on homeschooling?

Hi All- my daughter is 4 and we are/plan to homeschool. We enrolled her in martial arts a few weeks ago, and it’s set up so different kids can come on different days with varying weekly frequency. It’s been only awesome so far until today. The teachers had asked them where they go to school (the teachers are awesome and often go over basic safety stuff in little discussions). One kid heard her say she’s homeschooled, then turned around and shouted at her that she needs to go to real school (he was a much larger boy). My wife and I both gave a stern “no.” After class, I stopped his parents, told them what happened, and asked them to please talk to him. They looked surprised but agreed. I’m pretty sure that’s that, but my wife and I were genuinely surprised this happened at all (this is a 4-6 aged class, so I’d imagine quite a few aren’t in school yet). How often have some of you seasoned homeschool parents run across this?