Or: I agree with you, it shouldn't be that simple.

What I'm envisioning is that the noble motives are a cover for something deeper. It might be how she explains it to herself, it might be how the writers keep everything as morally ambiguous as this show needs to be (it would be dull for her to be the vanguard of the people, but it would also be dull if she's just an evil spiteful bitch who brought down poor Jimmy McGill).