Because apart from when he was hunting down Newt, Grindelwald had normal taste and behaved normally, without being as extreme as Voldemort.
Of course, as for hunting down Newt, judging by the history Professor Snape had learned...
It seemed Grindelwald was not to blame...
Who would not fly into a rage after the other fellow stole something so sacred?
A cautionary example like Voldemort was a different matter.
Voldemort, along with quite a few of her Death Eaters, had actually become extremely radical.
They often acted without any logic, and sometimes their only aim was to amuse themselves by killing or torturing others.
That had already strayed completely from being a group of Dark wizards with a defined agenda.
To Snape, this was a textbook sign of being deeply influenced by Dark Magic.
Were killing and torture not means to an end?
How had they become acts of pleasure?
That in itself was a betrayal of Dark Magic, as well as a rejection of the spirit of human rights.
If one approached Dark Magic critically and cautiously, one would not be affected too strongly.
Many ancient scholars of Dark Magic had not suffered particularly serious corruption, either.
In fact, as far as Snape knew, the ancient master of Dark Magic scholarship, Mr. Goldlock, had not only wielded the Elder Wand, but also conducted systematic research into Dark Magic.
Why had he not suffered severe corruption?
Where did the reason lie?
Professor Snape believed the reason lay in holding firmly to one's inner convictions.
In essence, this was actually the same as the "love" Headmaster Dumbledore spoke of.
To take a very straightforward example, all of them could cast the Patronus Charm.
A great power guarded their hearts, protecting their principles from being breached by harmful temptations and ensuring that their