Summary: Not from a legal/policy perspective, as the restriction only applies to Mainland Chinese residents. It is difficult to gauge how that affects the ferry you are planning to take though (given there will be less tourist traffic).
The BBC article the OP linked contains a link to a notice by the Ministry of Culture and Tourism of the PRC. It reads:
Grimaldi Lines Serves Tangier Med Port
In the centre of town? Or will we be stuck in a dark port some distance away from anything?
Unfortunately, the Grimaldi Lines ferry arrives in Tanger Med port, which is circa 40km away from the city. Assuming you do not have your own vehicle, there are several other transport options available to you.