Imperius isn’t fail-safe, you can’t Imperius strong-willed persons (at least not in cannon), I don’t think you can Imperius Voldemort, Lucius Malfoy, Dumbledore, Moody, … Even Harry can resist the Imperius in cannon.
And while it’s true for the “bad guys”, AK is more efficient than Obliviate, for the “good guys” who have restraints in killing (like Dumbledore and at least half of the Order of the Phoenix) using Obliviate on death eaters would seem much better than killing them or sending them to Azkaban. I always assumed they didn’t do it because it wasn’t that easy (long/delicate casting, don’t work on Occlumens, …) to wipe memories massively like that.
Lucius Malfoy claimed to be Imperiused during his time as a Death Eater. That claim needs to have been credible enough that his allies in the Wizengamot could use it to justify voting not to send him to Azkaban. That doesn’t mean it has to be very credible, of course. But it had better not have been common knowledge that Imperius only works on weaklings.
On the other hand, the good guys are bound by the law, which dictates that surviving Death Eaters go to Azkaban, whether Dumbledore and co. want it or not.
Imperius isn’t fail-safe, you can’t Imperius strong-willed persons (at least not in cannon), I don’t think you can Imperius Voldemort, Lucius Malfoy, Dumbledore, Moody, … Even Harry can resist the Imperius in cannon.
And while it’s true for the “bad guys”, AK is more efficient than Obliviate, for the “good guys” who have restraints in killing (like Dumbledore and at least half of the Order of the Phoenix) using Obliviate on death eaters would seem much better than killing them or sending them to Azkaban. I always assumed they didn’t do it because it wasn’t that easy (long/delicate casting, don’t work on Occlumens, …) to wipe memories massively like that.
Lucius Malfoy claimed to be Imperiused during his time as a Death Eater. That claim needs to have been credible enough that his allies in the Wizengamot could use it to justify voting not to send him to Azkaban. That doesn’t mean it has to be very credible, of course. But it had better not have been common knowledge that Imperius only works on weaklings.
I think it was more that it works for nearly everyone, not only on weaklings.
On the other hand, the good guys are bound by the law, which dictates that surviving Death Eaters go to Azkaban, whether Dumbledore and co. want it or not.