Not bashing any particular "doctor" but remember a few things. Most of these PhDs taks a while to achieve. Almost all these people got theirs before weed was legal, based on basic big-ag agriculture.
Among the outspoken ones only a few have bothered to show me their grow.
WE all know that weed is not just another plant when it comes to agricultural/horticultural needs. It spans the spectrum from produce (hemp seed is a food crop), industrial (hemp-crete, hemp rope, etc.), horticultural for the flower aspect, and medicinal.
We also know that no one has been able to legally grow weed other than 0.3% THC hemp for all their experiments until recently. ALL this science is new, and all of it is subject to change - that's how science works.