"Treat the cause, not the symptom" ^
If we're talking about mages going abomination during the Annulment, it's like... well duh. You've just announced that you're going to kill them indiscriminately for a crime they didn't commit, what were you expecting? If I were in that situation, I'd empty both barrels and then go abomination myself. No reason to go quietly.
Mages survived the anullment (the ones from the Solas' personal quest were from Kirkwall), if they become abominations they were weak from the start and Meredith was right when she said there was Maleficar among the Kirkwall's Circle. I would never support them. To me she was the lesser evil.
But whatever, BW made both faction idiots.