Some people don’t know how to respond to people who stutter. I don’t know this person, but I doubt it was said maliciously. There will always be people that say things like that, and it will come when you least expect it. I had a contractor that was bidding on some work on my house say something similar when I was explaining the job. It hurts, but we cannot let it control the narrative of our lives. There will always be bad actors, but I believe that it is safe to assume most people don’t intend to hurt you, they just don’t understand what’s happening and act inappropriately. Take that time to educate and explain that you have a stutter. Of course, all of these things are easy for me to say. I’ve had 32 years of experience stuttering my face off in some really terrible situations. It gets easier though. It takes hard work, but it does get easier.