Yes it looks like it has little or nothing to do with French protectionism. Speedferries haven't been paying their bills and that applies in Dover as well as in Boulogne. Seems the Port of Boulogne was the first to issue a writ for seizure.
Shame, Speedferries has been my preferred carrier for years now, and I have two unused return tickets, but I'd not put any money on them getting out of this one. Their finances must have been dodgy, as Garyfrogeye points out. Capacity is 200 cars - at £30 a car that makes £6000 per crossing - not a lot when you factor in fuel, staff costs, port fees and all the associated costs landside.