You were just retorting amygdala being the root cause with your own speculations while the presentation expert made it clear it was the 'cause'. So at least you gotta retort him with your own evidences, instead of just 'explaining away' this theory. Also hyperactive amygdala does not mean it's making you excessively afraid of speaking or similar. It can also function in 'threatening stimuli'(aka Valsalva response or whatnot) which means stuttering is perse a response to threats but we PWS are too hyperactive in this function so that's why we stutter.I can't prove this theory wrong but I gave my explanations. To recap, this theory implies that we PWS are too hyperactive in nature responses to threats(even when there were no threats but because of the hyperactivities of amygdala we naturally 'responded').