Oh heck, I failed my saving throw.
1. The reason that the 3 orders of wizards work together is because they have no choice. Let's not forget that there used to be 5 Towers of High Sorcery. What happened to the other 4, you ask? The other 4 were destroyed and all the wizards killed by the general population that tried very, very hard to exterminate every wizard in the world. The only reason that there are any wizards AT ALL in the setting is because of the Tower protecting wizards. The choice is work with the other robes or go extinct.
2. The Test of High Sorcery is rarely lethal. Nor does it typically scar the tested. Raistlin's test was corrupted by Fistandantilus. Most wizards pass and very few actually die in the Test. Yes, it can be dangerous and potentially lethal, but, killing wizards isn't the point of the Test.
3. This is a post apocalyptic setting. The heroes are heroic, true, but, the rest of the world is a very dark place. The first thing we learn about (or one of the first) is a story of how the townsfolk tried to burn Raistlin at the stake for exposing a charlatan. The elves are downright nasty. All the different races are at each other's throats long before the Dragon armies come along. The "heroic knights" are bigoted and also pretty nasty. Every group is out for themselves.
4. This is a setting where there is a considerable amount of nuance in morality. It's not something that just says, "Yup, the good guys are good and the evil guys are evil." The good guys are often pretty bad and are only really good guys in comparison to the really bad guys. Most of the races are xenophobic, isolationist and outright hostile to pretty much everyone else. Mostly because the races have all spend the last 300 years crawling out of the stone ages after the Cataclysm.
5. The Cataclysm is entirely background in the setting. We don't actually play during it. Make the Kingpriest evil if it makes you happy. There's no reason, particularly, that he has to be good aligned. He was in the books, but, really, that's probably more just a hold over from the earlier rules. Since alignment in 5e has zero mechanical impact, he doesn't actually need an alignment at all. Yeah, the Kingpriest is an evil bastard. At the end of the day though, since he spends exactly zero time on screen, who cares?
I've probably missed some stuff there, but, a lot of what you folks are arguing about is pointless setting minutia and a LOT of it is barely supported by the actual text of the modules or the books. It doesn't make for a particularly fruitful conversation when people are arguing what they think the setting says rather than what it actually says.
