Ahh, that sucks so much and I have had many situations where I was laughed or giggled at. I don’t think he broke any laws. Did you disclose your stutter as soon as you got there? Much of the time, a little chuckle or laugh is a person’s way to cope with an uncomfortable or awkward situation. If he openly laughed and mocked you, you would have something to formally complain about for sure. But a small chuckle should be chalked up to a coping mechanism.