Ever heard of the phrase "There is no black and white. There's only shades of gray"? I don't think that's entirely true. While the world isn't all black and white, it's not going to be all gray either. After all, black and white do make gray, and where would gray be without those? And one can't say that there is no such thing as good or evil when you look and see the good and bad things out there in the world. Examples include love, kindness, freedom, truth, and love for country/hate, contempt, slavery, lies, and disloyalty.
To elaborate, there can be left-wing people out there who preach about gray morality being superior, saying that there is no such thing as good or evil. But when it comes to people opposite them - like religious people, right-wing people, and those who disagree with LGBTUVWXYZ - they'll view those people as backwards-thinking, bigoted, or evil. There are some of those people on the right-wing that can be just as nutty, but I won't judge them all, just as I won't judge all left-wing people. Heck, I've even seen this kind of behavior on the Warrior Cats forum (I know I'm slamming that forum a lot, but I feel like they need some mud slung their way for once).
As for me, I myself have a rather black-and-white view on things. I'll see where there's gray, but I'll definitely stick with a simpler outlook on life. There is indeed both good and evil out there in the world, and to deny that or blur the lines too much sounds too complicated.