Maybe they're guessing that feeder pax are already not enticed to choose AF because of the business feeder flight. If everyone expects nothing with regard to the hard product (seat blocking can still be enforced in the booking engine, catering is already nothing to write home about, the seats are exactly the same...), maybe they figure they won't lose anybody by removing the product altogether. They might lose some of the very few customers still flying direct C flight, but it may not be much compared to the cost of marketing an intra-Europe business class product and managing the associated catering.