As I said - Henselt started war, Sabrina just finished that. Henselt brought men on the battlefield. If there wasn't Henselt (or someone like him), there would be no victims.
I don't blame someone, who just finished the war, I blame persons, which started that war. If there wasn't Sabrina, who would pay for thousands of dead bodies? ... No one - because it's normal to lead many men to death, buth when sorceress defeat both sides, that is problem? When you are in that battle, you are soldier of gray banner (I think) and you run for backups - before Sabrina could do anything, most of your comrades wasn't alive - whole banner died - and everything is ok? But when sorceress do that is that wrong?
When Seltric or Vandergrift (not sure) came to scene, you fighted with some soldier - "honor fight" and what he did? He asked you for mercy, you gave him that, but that idiot just killed him - that is noble war and fight? To kill own soldier who simply lost normal fight? As well as he hanged every third scout (he couldn't know if that was trully their fault).
Historically, Henselt was in the right. Aedirn took Lormark from Kaedwen, and Henselt simply wanted a piece of native Kaedweni land back.
That is not whole truth.

Lormark was part of Aedirn - just Henselt used war with Nilfgaard as reason, for his "help" to people of North Aedirn. If I remember correctly, he is just liar, which build his reason on his few years old invasion into Aedirn. Demawend told him, how acted his army - read about this and then you can compare that with acts of Sabrina.
Does any conventional war gives a right to any idiot with a nuke to drop it and irradiate both sides?
I see that in different light - I see no reason, why some idiot even starts that war. And all faults is on his head.
Nuke is not perfect thing to compare with - this spell just killed a lot of SOLDIERS - men which came there for death or to kill. And they get that - maybe more they ever wanted, but I don't see any problem there.
Kings (emperor) led thousands and thousands men to death, just for their power. For bigger lands, for glory and other silly reasons. Thousand men died, thousands civilian people were killed, whole countries were burned ... that is your "regular" war by noble kings.
I already compared acts of sorceresses and acts of kings, but - just for you

...
Loc Muinne for example - I always hear, how Philippa (or Sheala) was cruel, when she wanted to burn that city down - but there were mainly armies, envys, kings and other non-civilian persons, but even that - it was terrible, but when regullar army raid that city, killed all civilian inhabitants, all children and women, that was fine? Or when Emhy burned down whole countries - that was fine, because that was regullar war, no matter how many innocent people died, but when is just one city burned down, is that the problem?
(of course, not only emperor's army did that things)
I don't really get why anybody even conceive to justify Sabrina's actions. I can get what reasons people may have to justify Hiroshima
I can't justify agressive actions - like wars, not weapons, which ends that war. I don't believe in any "honor deaths", regullar weapons,... when someone starts war, he has to count with death. There are just two things, which are important for me - who started that and what about innocent people.
Hiroshima was also civilian city, if only military base was hit, by weapon, which kills just soldiers, there would be no doubts about that action.
She was a state official, it was her duty to attend to well-being of Kaedweni nation, but she chose to mass-murder her own people, those she was supposed to protect from magical danger.
She was member of the Lodge and I believe in their actions. I think their state should be better than Kaedwen or Aedirn, Temeria,...
I don't really get why anybody can feel in the right when they disregard the duties they have here and now
Henselt had duties from Cintra and he "pissed on it", so why he could count on duties of others?
in favor of some abstract principle, or some idealistic, or utopic political system, and start perpetrating heinous crimes with ease.
Show me side, which didn't do any crime..
She burned them alive - Henselt burned her alive. Justice served.
And what about his attacks and wars which he started - same princip of justice - kill him same way, how human died because of him?
It is very sad that when something does not go their way, some sorceresses go for a mass murder by fire. Sabrina massacring two armies, Philippa and Sile ready to burn alive the entire Loc Muinne, including all the sorcerers in there...
Of course - Loc Muinne ..

how many people were burned alive or killed by armies of each side? How many towns burned down Nilfgaard,...?
And what about that ending, where were all sorceresses in Loc Muinne killed by that idiots? Is that better?