Wow, that is a complicated question. I don't think there is a clear cut answer, it just massively depends on what you define as evil. I personally believe strongly in "right and wrong" but not absolutely pure evil. Of course I also don't pretend to know everything either, so I admit I may be totally wrong.
I think that "made evil" people have a reason in their own head that they do depraved and cruel things. Whether they do them because they are misguided enough that they actually think they are doing the right thing or they are severely warped and in pain and spreading that pain and cruelty is the only escape they have.
As far as people born evil, most people are thinking of psychopaths. There is so much fear and misinformation about them. A psychopath is simply someone due to some brain malformation doesn't experience higher level human emotions. They are no more evil than any other animal and 99% of psychopaths go about their lives doing no more evil things than every other "normal" person. They aren't motivated to do "evil" things because they don't have the emotions that urge them to do so. In most cases they rely on logic, and evil just isn't logical most of the time. They are simply how they are born, and I feel they deserve pity more than our fear. After all, none of them will ever feel the incredible joy and and love I can feel every day.
Don't get me wrong, there are really fucked up people out there. And when a psychopath with stunted emotions gets combined with a warped personality and or violent tendancies you get some pretty evil stuff. I'm just saying I don't believe that there is never another side to things, and I have a hard time accepting anything can be absolutely evil.