The goal wasn’t “false”.
The cinematic proves that the Jailer was in fact a “true” ruler of the Shadowlands.
Regardless of whether Sylvanas gamble on him ended up badly, fact remains that the system had been patently manipulated in a way that removed the “original” ruler, and put in its place an automaton controlled by who knows what to do something we’ve yet to know.
If the premise behind Sylvanas actions was “I’m going to fix this borked system”, then she was indeed acting towards the goal set.
Still, much of it is irrelevant to the loyalist alternative.
The only thing asked for them was to believe that Sylvanas operated on information nobody else knew about, and was working towards some greater goal that demanded certain degree of sacrifice. And that much is true.
Whether you consider it agreeable, or how the payoff ended up being, is beyond the point.
This all reeks of your own personal opinion. And goes against the explicit information (whoever little), we’ve just been given in this exact cinematic.
One where Sylvanas tried to stop Zovaal from causing unnecessary harm to Thrall, Bolvar and Jaina, and downright turned against him after a regretful glance at what he had done to Anduin.
Lol. Why?
Now being fooled makes someone a villain too?
Because yeah, having Sylvanas beaten by her own ego to the point it clouded the rather obvious warning signs surrounding a dude literally imbued in Domination magic, is sort of dumb.
But that doesn’t make her any more villainous, nor does it negate the fundamentals behind the loyalist premise. Even if it certainly cheapens the experience behind it.
Remember when the Church of the Holy Light followed blindly the Twilight Father? Or when Night Elves created a mountain size piece of wood to serve as key for Old God contamination, under the orders of someone that wanted to usher the Nightmare to destroy reality?
Or when humans were led by a Black dragon?
Every race/faction has had its time wearing the fool’s hat. And same could be said regarding characters.
Honestly, Sylvanas is but a few steps behind Illidan in terms of motivations, actions, and impact on those that surround them.
And he ended up as a hero of sorts.