Some of the 'arguments' that have been used by vegans to deny the biological reality of their digestive tracks in support of their preferred way of eating are pretty out there. The latest video making its rounds on FB featuring Dr. Milton Mills is certainly no exception.
Don't know about anyone else, but if this was my doctor I'd be looking for a new one ASAP.
A good dissection of the doctor's claims can be found here:
https://www.sott.net/article/374794-Stupid-Things-Vegans-Say-The-Word-Salad-of-Dr-Milton-Mills#