Jana already mentioned how she felt about Vanessa van Cleef: she wanted to be able to help her, but due to the linear nature of the on-rails world that is Azeroth, she was unable. I sympathize. I felt the same about both her and her father, Edwin. I felt thoroughly ashamed that I helped Thrall escape from prison and killed Alliance guardsmen to do it (I will never do this instance again on any alt), and I was unhappy about killing members of the Scarlet Crusade/Scarlet Onslaught, whose aims I thoroughly agree with (even if their leadership had been infiltrated by our enemies).
We are not allowed to behave differently, though. I cannot join the Scarlet Crusade, much as I would like to. Its members are red to me and attack me on sight (members of the Zandalar tribe also attack me on sight, despite the fact that I am supposedly exalted with them). No doubt many orc adventurers felt troubled by helping Garrosh steal the Divine Bell, while other orcs must feel terrible about betraying him. What can they do about it, though? We are all on rails.