Hi comatose. I wouldn't say evil is a tangible thing. It is simply the absense of enlightenment. The increase of enlightenment goes hand in hand with the decrease of evil acts.
Free will by it's very nature must include unenlightened acts.
What if a well-to-do father made it the mission of his life to never allow his son to fail at something. At school if the son was doing poorly the father paid off teachers to make sure they gave his son an A in every subject. When the son graduated the father pulled strings not only to get him a good job but made sure by payoffs or threats everyone treated his son like he was the smartest person in the company. Would the son have learned much in his life? Would not the "love" of the father actually be selfishness in not wanting any son of his to be seen as failing at something?
Failing at something is a fairly big way how we as humans learn lessons. We can do anything we decide to do. This is the universal law of free will. Another universal law is the law of karma, reaping what we sow, or whatever you want to call it.
It is not unfair of the creator to make it so that if a human is selfish, close-minded, jealous etc. that human will be unhappy. Likewise if a human becomes enlightened and realizes his oneness with every other human and correspondingly loves all like he loves himself he will be happy and feel fulfillled.
These are lessons we learn in the schoolroom called Earth.