I've had countless interviews like this before - even some where one of the interview panel smirked after I stuttered. What I took from that is that these would be toxic places to work and it was good riddance. I was lucky to find my current job where despite stuttering in the interview (and thinking I failed because of it) they offered me a job because of the skills I offered and my personality. I know it's easy for me to say but stick in there. You will come across a job who value you as a person regardless of any stutter.