If you read the article the main argument the author was putting forward is that in society, you will naturally have some people that are outspoken and loud, others timid and shy and those in between. The different dynamics between these group of people arises different roles for them. The outspoken ones will lead and the shy ones will follow and lack confidence to voice their opinion. The author is thus putting forth that stuttering is an evolutionary trait intended to supress the pws to put him at a disadvantaged in society by self-suppression. The same way back in our hunter gathering days men who were not physically strong were disadvantaged in mating and hunting. I agree with the social dynamic's part, but not that stuttering serves that specific purpose in society, the same way depression, adhd or any other disability doesn't.