It's not that simple.
It comes down to Money.
Cx employ freighter Pilot's on a lot less money than Pax Pilot's for essentially the same job. A lot of Freighter crew are leaving and a lot more wont join on the crap money Cx offer. We Pax Pilot's wont "prop up" their lack of Freighter crew and fly the Freighter and get Cx out of a crewing hole. To attract and keep Freighter Pilots the company will be forced to pay ......etc etc
Cx are just being cheap charlies and by us not flying the Freighter they will be forced to up the Pay to a unified scale.
Get it?