I blame the way people are brought up all their lives. In my country, we legit have media that uses people with a stutter for laughs and gags and they are ridiculed EVERY single time, though recently, I don't see such content much anymore. It's the way people are taught that fluency and fluent speech is the hallmark of normalcy, that's that fault. It almost becomes an instinct to be weary of or laugh at something like a stutter. The change needs to come from the beginning of socialization, but then again maybe what I'm talking about is only a part of the problem.