He could be, you don’t know. Either way, a call to authority is a weak rebuttal. If you don’t know enough to counter his assertion head on then you likely know less than him. It may be Reddit, but a user who provides seemingly informed comments like the one in question on a sub-thread of this kind of study might actually have an informed opinion. Reddit is a large community and their are thousands of scientists involved in the research of cannabis at the moment, it’s a current hot-topic of discussion, after all.

I’m not picking up on how it’s tongue-in-cheek, it seems like a direct callout. Guess I’ll just have to take your word on it

It sounds like he/she is knowledgeable and also has experience/familiarity in this field of study. There is no need to pose a call to authority based off what they said