It's not my job to educate you on the basics of a given faction in a thread dedicated to it. Especially since your ignorance on the topic smells of you feigning it.
Given how your post opened with you challenging @Arrashi to even name those differences, that's a rather peculiar way to phrase that point. And last time I checked I already pointed out how your points #2 and #3 in regards to Forsaken are a fabrication on your part. Which, lo and behold, included the entire bit about them wishing to destroy all life in the same manner as the Scourge. The Forsaken are ruthless, cruel and merciless to their enemies, but their wish to destroy life (or unlife in the case of the Scourge) is limited to their enemies. And even then, only in the capacity that makes them a threat.
Vide their fight against the Alliance that ended in 4.0. Was Alliance still an enemy of them after 4.0? Most certainly, given how at the very least it was at war with the Horde, the faction that Forsaken joined. Yet after Forsaken secured their borders and felt secure in their kingdom (even with a few Alliance outposts remaining right on their doorstep like the Aerie Peak) they sat out the reminder of that faction war, with Sylvanas only sending a token force to Theramore and Krasarang and only because in those cases Garrosh demanded that (because at least in case of Theramore she was against that campaign).
Forsaken are inherently an isolationist force. Precisely because of what led them to take the name of Forsaken. They don't like the living, the living don't like them, as such they prefer to be separate in their own corner of the world or, to some degree, mingle with the Horde that isn't antagonistic to them. And as long as the Alliance or any other unfriendly living force doesn't bother them, they don't really give a shit about them.
And your defense of your second point is just sad. Oh noes, the Forsaken developed a weapon. Wait, would you look at that, the Alliance developed nukes. Those Gnomes must be an enemy of all life and as such should have been purged. Stellar logic right here And what innocent test subjects? The test subjects we know of were captured Scarlet Crusaders, some Dwarves from Dun'garok garrison, soome militia members of Hillsbrad and Forsaken's own criminals to test its capacity against the undead. And if you know your Wrathgate example is bad, why even bother making it?
And your last paragraph is a pile of bullshit that has nothing to do with this thread to begin with, that you made up only to pretend you have shit to fling in my direction in order to besmirch me and dismiss me, because having actual arguments is too hard. Which in turn is the trend with people that conjure a pillar of salt whenever Sylvanas is mentioned.
But to address what you said there specifically, the claim that Sylvanas murdered people that even remotely threatened her power over the Forsaken is a falsehood on your part. Which makes your flimsy remarks about headcanon rather ironic. Because Sylvanas only ever killed people that betrayed her, i.e. the folks that stole her bloodstones and defected to the Kirin Tor, Varimathras, Stillwater and the Desolate Council members that shat the bed at the Gathering. And from outside people, Calia, who was openly encouraging the aforementioned Desolate Council members to defect. And given how she is the highest authority of the Forsaken society, her punishing traitors does not constitute murder, because words mean things. And in regards to her conning the Forsaken, it was already addressed in detail by @Super Dickmann.
The people that try to pin all of Forsaken's behavior on Sylvanas are outright admitting they have no clue about the race. The Forsaken act the way they act because they are undead and their very state of being gives them a rather limited emotional range. They needed no Sylvanas to do plenty of fucked up shit with her nowhere in sight. For god's sake, half of the traitor forces Sylvanas had to deal with were people that didn't think Sylvanas went far enough, with Putress allying with the Legion to make sure everyone he hated died and Stillwater decided that Sylvanas' limitations on necromantic practices were not in Forsaken's interests.
And Sylvanas didn't off anyone who would have a different view from her. The Forsaken that left to the Argent Dawn/Crusade were left alone even when they were openly critical of her. Same applies to plenty other undead who went their way. Let alone the undead resurrected by them that refused to join, vide Voss or Robrain before they teamed up with the intent of attacking the Forsaken. Sylvanas only punished people that actively betrayed her, be it by stealing from her, defecting to her enemies, making secret pacts with her enemies or breaking her laws. Magically enough the Desolate Council members wasn't entirely destroyed and the people that didn't, you know, try to defect to the Alliance or violate her orders about the retreat survived just fine regardless of whether they agreed with her on the Eyir thing or not.
Oh, yes, because the Forsaken just love the light. It's not like the Light actively hurts them which made them feel even more forsaken when they were trying to find their place in the world anew.
Eh, the retcon didn't go that far. It only said Sylvanas wasn't against the overall prospect. But in the end Garrosh still began the invasion on his own while Sylvanas was still on her Icecrown suicide trip. And given its intended purpose, it's not like she initially intended to be a part of the invasion on Gilneas.