The reality is, you just have to teach them how to reprisal/feint/addle. This is a team game, and when you sign up for PF M12S, you need to have patience. Yeah, it does suck when your party is dying to the first raidwide constantly at the very start of the pull, but everyone goes through that. Your standards are way too high to expect people who are on the final floor of the savage tier to mitigate, only world first raiders do that.

And sure, prog liars might join your group, but have you considered it will take you longer to fill the PF if you exclude them? You have two options: you either deal with the prog liar, and you get 30 minutes of p1 prog after waiting in PF for hours .. or you wait in PF for these magical unicorns that are so good at the game that they are able to mitigate, who may never show up. I personally would take the former, because even if I didn't get any prog myself, I at least helped the prog liar to get further. So overall, the happiness in PF increases.

Hardcore content will not survive if you stay on this trajectory, because as we all know, people will quit in droves if you exclude the prog liars, especially after a couple of dozen of bad pulls.