Why do some people act like having a stutter is all in the head?

Why do some people act like having a stutter is all in the head? Why do some people ask like having a stutter is all mental/psychological? People say ‘just practice bro, just be confident bro’. And it seems that it’s a lot of right-wingers/conservatives saying that and having that mindset because they think ‘A man thinks as he is’ (or something like that). What about the people who did EVERYTHING and put in all the hard work and still don’t have any results??! Why do people think it’s so curable?