(Welp, this comment turned out longer than I expected...)
Depends on your view point of the world. I probably should have said "Some humans are inherently evil" or "humans have evil thrust upon them and some choose to take it". Or something else entirely.
Evil is defined by actions YOU, as a person, don't agree with. For instance; supporters of ISIS won't see what they are doing as "Evil" because they think they are the good guys and their enemies are fighting for all the wrong reasons.
For me, humans are evil. We may do lots good but we also do a lot bad. Look at Barcelona recently, or North Korea. But at the same time the only reason I see those sides of humans is because that's the only part I see due to media. If you or anyone misses all this bad then they could easily percieve humanity as good since there is no thing called "Bad guys" and "good guys" in this world, only the victors and losers.
Look, if you want a arguement backing up my original statement look no further than back in history; Gladiators for example (first example that came to mind. I can't be bothered to search for more). The reason so many existed was because romans ENJOYED watching others die. You can make the arguement that humans kill each other as much as animals kill their own species, but the differences is that Humans understand Morals.