While this may change at some unkown distant point in the future, in general, FS Marriotts charge for Internet access (including to elites.) So unfortunately, your experience is par for the course.

A lot of the "lower-end" brands (Courtyards, Fairfield Inns, etc.) include internet access with the rate though. So if you are looking at free internet from Marriott Branded hotels, I would suggest looking there.