"What if your boring, OP, unstoppable Kirito-protagonist was the villain instead." isn't THAT much more interesting.
And that was a little tolerable, when the humans were the aggressors in earlier seasons.
But this entire season was watching a bunch of good, noble, honorable people getting cruelly massacred over and over. An entire kingdom of innocent people are murdered for the optics. I guess I just don't see the appeal of that.