I don't think it has anything to do with the art per se. I mean, why should the fact that you're on an "aikido journey", so-called, be the reason why you question whether or not it is appropriate to smoke marijuana? The question makes no sense to me. It's like asking, "Should you eat pork rinds if you're a CPA?"
Exactly. It's an irrational question. Besides, if one wanted to take a "journey", or a "trip", Mary-Jo wouldn't exactly be the drug of choice.
So, smoke, drink, and eat crispy pork rinds if you must - preferably in the comfort of your own adobe. It's your choice. What sort of "journey" do you want to experience?