Okay so call me simple minded if you will but it seems as though we forget that this word (and most others) has/have a very clear and defined meaning.
Evil- Profoundly immoral and wicked
For those who don't know
Immoral- Not conforming to accepted standards of morality.
So if the general consensus of the world is it is morally incorrect to do something than it is evil. I don't believe evil is a subjective word either. It has a clear and defined definition. As simplified as it may seem evil is based off majority wins. If the majority of people believe something is immoral then by definition it is evil.
For example; the general consensus of the world is it is unacceptable/immoral to rape children. Therefore to rape a child is evil. To hold someone against their will and torture/kill them is considered immoral by majority. Hence its evil. We need to be careful how we throw our words about. We use them to freely not thinking what they truly mean and are defined as.
Now to be very fair as much as I can be to myself at least, the word evil may at one point been subjective. When our society had a stronger base in christian religion or when they were more powerful in our ruling bodies, may be a better way of saying it, this word might be up for debate. Though as we have grown and progressed the word no longer has a definition strongly based off a religious concept.