It's not a rule, persay, that herbalists need to be a little.. eccentric to be chosen for such a role. More a rule of thumb.
It is, however, rarely wrong.
I mean, what kind of weirdo wants to stare at plants all day long? Who has the patience, the discerning eye, and the wisdom of returning to the soil from which something was taken?
Axolodi has everything but the patience.
His favorite past time is, of course, messing with inquisitive little pups. As for adults? His days of outright challenging anyone who so much looked at him wrong are over- he's no longer that young, unruly pup. But that doesn't mean he'll tolerate untoward behavior. He's fun and playful; until you cross that line that disrespects him or his hard work. Silly does not mean stupid. And kindness is not weakness. He has no obligation to either.
He knows his role may be outlandish to some- but he is the one you're coming to when injured, after all.
Herbalist 
Herbalist