Customer's kids were making fun at my stutter and the parents did nothing about it.

Customer's kids were making fun at my stutter and the parents did nothing about it. So I was serving some parents at my job and I stuttered. Their kids started laughing and mimicking my stutter which I ignored. Kids are kids. They laugh at random things, which is understandable. But I was annoyed the parents didn't say anything like they thought it was ok.