Yes, it is incredibly frustrating and disrespectful when someone cuts you off because of a stutter. It can 100% make you want to fade out and not be a part of the conversation. Truthfully, I don’t think people realize or don’t intend to be rude when they do it. It was awkward at first, but I’ve had decent luck politely asking the person who cut me off if they mind if I finish what I was saying. Not in a rude or mean way, just a “Oh I actually wasn’t finished. Do you mind if I finish my thought?”