Its misplaced to have a go at the training captains.
I'm not one. I'm a very plain vanilla captain. However, the 10 -15% extra pay you get as a training captain is a sizeable deal. You can't jeopardize it by refusing and choosing who you fly with. If you tried that on then you'd be taking unofficial industrial action. You could be fired and sued for costs arising from your actions. You'd certainly give yourself a 10 - 15% pay cut at the very least.
Training captains train. They don't set industrial relations policy nor recruitment strategy. They just volunteer to fly with crap trainees, offer advice and fill in the paperwork afterwards. Its not glamorous, they are readily replaceable and they have no control over anything not connected to the aircraft they are currently strapped to.
WWW