But if the contracted player says no what can you do? I'm sure all the players mentioned can leave for nothing.

Painful as it might be on the field, it is right that the club honours its commitments, it's not the players' fault the club signed them up is it?
I would be surprised if any of these mentioned are still with us in 2020, possible exception of Golding.
Ferres is an interesting one for me; I'm guessing he's on good money and when he's fit he's probably worth it. But what do the club do if he's having a good season this year, given the previous two?

Well Ryan Bailey managed it for years blowing hot n cold. Hot when his contract was up, cold when he didn't have to put it in. I for one really hope Ferres turns it around, early signs are positive but hes just cursed with injuries.

I get your point and the approach isn’t very ”humanitarian”, but the answer is you tell them they will sit in the stands and not play, meaning their value to their next employer might not be what it is now.

It's not about "humanitarianism", it's about decency and professionalism I would suggest. The culture of the club/organisation is more important than expedience because we made some errors of judgement. As a club we need to take our medicine and get on with it.
Leeds built an unprecedented era of success on developing a culture which produced a winning side. You don't get that by stiff-arming employees when it suits you IMO.
The old mistakes will be washed out of the system in another season or two, to be replaced by brand new mistakes no doubt!