It is true. Sure, she might be undead and an elf, but she's giving the Horde what Thrall took from them and that's being brutal and unhinged when it comes to the enemies of the Horde. Garrosh tried to provide the same leading figure through himself and Sylvanas is no different, but she has far more personal goals and objectives behind what she does and while she temporarily provides some of the Horde with what they've desired, their interests and well-being is not her priority.