I only came across a few foreign motorcyclists during these few days, because of the weather surely as it was not usual to be as lucky as I was and only get real proper rain on the last day there. I would NOT choose December as the month to go ride motorcycles in Morocco if given the choice.
Out of those small numbers, one was a group of yellow plated bikes with a ktm890, a previous generation R1200GSA and a Tenere 700, the others the lone R1250GSA, an Italian R1100GS, and two riders on Himalayans. All of them can do it, but I much rather prefer to spend long hours on a comfy bike which uses a third of its available torque to ride along and have the rest to not be stuck behind smoky traffic.
Moroccans cross the country in mopeds that sip fuel at 60kmh which bicycle tires, but I much prefer to be able to ride past traffic than be a part of it.