It's not a bad definition. You're just wrongly applying alignment to shit like sheep.
There is a huge difference between people who do bad things as a means to survive and evil. Evil is someone like Shar, who wants to destroy all of existence because she hates everything, to cause suffering and pain for no other reason than because she is spiteful. But some poor soul who is starving to death being taken in by Shar's loyal people and being offered a place where he can belong, have shelter and food, accepting to do terrible acts in the name of Shar is not by default evil...he does what he must to survive. Nobody else offered him pity or help when he was about to die in the streets so why would he feel obligated to sacrifice anything for the good of those who couldn't care less about him? There are a lot of nuances here...but putting your own well being above the well being of others is not inherently evil at all.
