I've heard several people use the word "Evil" here in my short time on the forum. It seems like there may (or may not) be some confusion about this term. I'd like to offer my personal opinion about what it means.
The universe seems to be a finite entity. It isn't eternal. Something or rather someone began it. That someone would have the right to define the purpose of each thing created. To act contrary to the purpose of the creator would seem to be a good definition of the word evil.
That is one, particularly biased perspective. Particularly on this site, where beliefs are very mixed, even if you managed to get everyone to agree that one being is responsible for the creation of everything, you would never be able to get them to agree on who that being is or was. Therefore you could never get them to unanimously agree in accordance with whose will are good deeds done in. Even faiths that believe in the same god cannot agree with what that god's wishes are. Judaism, Christianity, and Islam are all Abrahamic faiths, worshiping the same creator, yet none agree on how to worship him. Even among themselves they cannot decide. The Christians are divided into Orthodox, Catholic, and Protestant, and those sects are divided still into multiple sub-denominations. Jusaism is split into Orthodox, Conservative, Reconstructionist and Reform. Islam is split into Sunni, Shia, Sufi, and Quranist. Even members of the same faith cannot agree what their god wants. It is nothing short of impossible to convince everyone that their is a single creator, who that creator is, and what that creator wants, in order to define evil by your specifications.
to quote John Oliver 'everything falls on what i like to call the Hitler/Hanks scale' there is nothing thats 100% good or evil, everythings a gradient, with the most extreme examples being on the end [in the Oliver quote Hitler being the worst, Tom Hanks being the best and everything else falls in the middle somewhere]
this is most simply true in pagan practices as the vast majority [i would like to say all but i'm sure there are a few exceptions] believe in duality and balance, and nothing being 100% good or evil. love spells can be seen as good, say you use the spell to attract more love into your life, but it can also be seen as evil if you're trying to get a specific person to fall in love with you. curses are seen as evil because you're intentionally harming someone, but what if this person is a murderer? lets say this same murderer is badly injured, is it good or evil to heal them? nothing is ever black and white, good or bad.
also in most pagan circles there isn't one all good deity and one all bad [as seen in Christian religions] to be punished or rewarded its all in the afterlife by these beings, and when we do bad it's because we were tempted by evil and lead astray. we are responsible for our destiny, we choose to curse an ex, heal a friend, bring luck into our lives etc. but if that turns out for the better or worse will be the result of the energy we put out and how/when it will return to us over time. this isn't to say the threefold law or karma is correct or the true law of the land [morality is personal] simply we have energy around us and inside us, we can effect this energy to attract like-minded energies/people/situations so if you go around in a bad mood grumbling about people being mean, don't be surprised when people treat you badly.
as for using the word 'evil' i think it falls into my mom and grandmothers view on the word 'hate'. to them, 'hate' means kill, so unless you dislike someone so much you wish to kill them, don't use the word 'hate'. hate is an overused word in our culture [Gods know i use it a lot more than i like] so i feel 'evil' for many, falls into the same category, a powerful word to voice their feelings in the moment to create an extreme, without fully grasping the deeper meaning behind it. idk if you've seen Dead Poet Society [or at least look up some of Robin Williams scenes] but there is an early scene where he talks about language and the use of lazy language, so say you're morose, not 'very sad' for instance. instead of hate you could use distaste, instead of evil you could use cruel, but we won't because we're lazy and choose the simplest terms to get our points across [as seen in my four paragraph response lol]
From my POV regarding to my waking life and towards witchcraft everything has a purpose within this world whether its negative, positive or neutral. In order for this world to turn and remain in balance there needs to be a positive and negative aspect where this also creates things such that is neurtal.
If the world were to constantly act upon negativity too much without the correct amount of positivity then the world will be more of an unpleasant place to life then it already is today and verse visa towards too much positivity. Well thats my two cents upon the situation.