The undead just want to be accepted
The small interlude with Sylvanas in the book
Arthas: Rise of the Lich King suggests that the Banshee Queen is what most people would describe as 'evil'.
The Royal Apothecary Society did almost all of their experiments with her consent. Do you want to know why she was pissed? Because they acted too early. If they'd waited, she'd have been stood alongside Putress screaming death to the Scourge and death to the living.
Wrynn being (in my book) a complete asshole (all he cares about is his personal vendetta, screwing it up for everyone, he's an awfull king).
Personal vendetta? Please. He's acting in the best interest of his country and the fact that he hasn't gone and marched all over Lordaeron is a testament to his patience. The Forsaken are in no position at all to stand up to Stormwind (which is easily the largest faction by at least four times as much as the Orcs) and the dwarves of Ironforge. If Varian committed himself to taking Capital City, a place he holds dear to his heart, he could do so.
But he hasn't. Interesting that.
Then there's the whole Garrosh farce (Watch the Ulduar trailer. Check who draws their weapons first. Check who knocks down the most powerful sorceress in the land.). There are only so many affronts to his nation he can take. Peace for the sake of peace has you come off as weak. Again, people think so little of Jaina that they have no issue with running over her because she comes off as a weak leader. Varian, on the other hand, is obviously ready to do what needs to be done.
And on top of that, there's the whole mess with Garona. So, look at it from this way: You've gone to a peace negotiation with the Horde, no weapons allowed. During this time, you see the Half Orc who murdered your father in front of your innocent child eyes. You not only see her, she's come to assassinate you as well. This Half Orc who, by the way, killed your father under orders from the Old Horde.
What would you think? A no weapons negotiation with a Horde assassin come to kill you? I'd be pretty goddamn pissed at the Horde as well. Yes, she
wasn't acting under orders from the Horde, but what reason does Varian have to believe that? He's had nothing but poor encounters with them since the day they walktzed through the Dark Portal.
And yet, he was one of the main proponents for the internment camps. He's a merciful king and you know it. Most people will scoff and say "Internment camps, Amnestic? But those are most certainly bad!" and I would respond: No. They're not. Your land has been beset by strange, green skinned invaders who have killed and plundered their way across your homeland, killed your father and the people you held dearest to you and ransacked your home city.
Eventually however, they're defeated. You now have three choices: Let them go, which is foolish by any stretch of the imagination. You could murder every last one of them, which is what most people would do. After all, they owe nothing to these invaders who clearly aren't human and they have caused unhealable pain to the populace of Stormwind. Or, you could keep them in camps where they would be both protected from outside mobs and couldn't regroup to attack them.
And Varian supported the camps! The most kind choice to both his people and the invading orcs. Personal vendetta
indeed.
/rant off
