Well, they are the bane of the world, technically. The majority of occurrences, negative ones that is, have Tailed Beasts at the fore front. However, in actuality, mankind itself is also to blame, Sasuke ignores this, while Naruto does not/cannot and wishes for the beasts to get along with humanity. Sasuke does not see this possibility while Naruto does. It's not a black and white, good vs evil situation, it's far more complicated than that.
It's like Danzo killing the Uchiha (except without the all together immoral means used to accomplish this, e.g. coercing a 13 yr old, mutilating your old comrades/friends son/grandson). Funnily enough, I've seen many place this event into a moral grey area, yet, Danzo never allowed Hiruzen his diplomacy, and had an entire group of people murdered, even innocents. Essentially, it's comparable, but not as deplorable. So, labeling Danzo morally grey and not Sasuke is hypocritical. Not implying that you do, just seen this around recently.
Madara's way, however, takes free will out of the equation. Sasuke has never shown this as part of his goal, Orochimaru helping Tsunade is proof of this.