If Jory freaks out about darkspawn and darkspawn blood
then he shouldn't be joining an organization devoted to fighting them on a daily basis.
The Joining involves Mages and Lyrium and blood, but it is not blood magic. Blood Magic involves the use of life force, through blood, to power magic and spells. Since the Mages are using lyrium, they're obviously not using blood. Moreover, it's not men's blood that being used anyway - it's darkspawn blood. So even if it was being used to power the ritual, which it wasn't, there should not have been any issue whatsoever.
KalosCast:He was trained to be ready for those things, he was not trained for his superior officer to go all creepy-stare cultist on him. It's a completely different kind of setting that he'd probably had no experience with. Using what little ingame knowledge that we're really given of him, that's the best explanation I can come up with without settling on meta-game principles like calling him various forms of plot device.
It's different. That doesn't mean it's worse. Duncan wasn't going all "creepy-stare cultist" on him. That's just a rhetorical exaggeration. He looked no different than he had before - if you thought he looked creepy then, then he always looked creepy, and if the creepy leaders are bugging you out, then join some other fighting force.
It's not like Loghain didn't look creepier.
Akka le Vil:Yeah, right. I'm pretty sure you've a lot of experience fighting Darkspawn to confirm that 
If you're going to assume unprovable apriori statements about everything and then proceed to undermine my integrity through veiled attacks, then there is no point in a continuing response. Is that your intent?
Do you have as much experience about fighting hand to hand someone that is really going to harm you than fighting darkspawn, or have you been robotized into blocking every emotion ?
Everyone feels emotion, man, especially fear. Some guys throw up before every mission. It doesn't stop them from doing their job and it doesn't drive them to aim lethal weapons at their commanding officers.
The point isn't that Jory felt fear. Everybody feels fear - it's normal. What makes Jory different is that he allowed his fear to drive him to make several very stupid decisions.
Because you don't look down on someone when you don't even have an idea of what he's facing ?
Seems pretty basic behaviour to me?
Jory wasn't facing something inhumanly horrific. Clearly, many people have done the ritual and not only that, but also survived and continue to live through everyday life thereafter. It's not impossible. We don't even have reports of Grey Wardens who survived but were driven permanently insane by the ritual - whether or not it happens, it can't be happening that often.
However, we
do get real reports of soldiers being driven mentally unstable from being shelled too long or being in too horrific a combat. Some of those guys never really recover. Many of them die during the combat that triggers the illness. That doesn't make treason acceptable.
Obliterati:Duncan wants Jory to drink the blood of a darkspawn, which is, as far as Jory knows, instantly fatal. Not to mention that Jory seems to be a dedicated...uhh, Chantry-worshipper...Chantryite? Chantrist? Anyway, he's religious. I'm relatively sure the Chantry would frown on the Warden's extremely blasphemous use of blood-magic rituals. To make an analogy, try telling a dedicated Muslim soldier he needs to take part in a secret magic ritual that involves drinking a cup of arsenic-laced pig's blood. I'm thinking he might react emotionally as well...and it's hard to argue that he's wrong.
Jory knows that the blood of Darkspawn is NOT 100% fatal - because he has two examples of survivors asking him to do it. He knows it's
instantly fatal, but that's a good thing - when
I die, I would like to have it be quick, God willing.
Also, see above. The Joining is not blood magic.