Yes very hard to watch / hear for me too. I think the reason for me is that I internalised the belief that people who stammer are somewhat inferior (as I probably think so of myself) therefore any time I spend watching / hearing stammer I think it’s not worth it and I feel like I have to distance myself immediately. Which is funny because while I stammer myself something in me it’s triggered that says “I’m not like these people, I am better, I don’t belong to this category of people”. It’s horrible to say but it’s true and I am trying to tackle this with my therapist.