Diablo III: Reaper of Souls

Does the reflect damage thing not apply only to gear since it says "affix"? Or does it actually apply to monsters?
Alternatively, I've never played anything other than a monk, so I might be missing some highly vital info.

Not sure what you mean. Generally whenever I fight against a mob pack with Damage Reflect, the meteors from Tal'Rasha will 2-3 shot me from full life cause they hit so hard. Granted this could change cause only one monster within the pack will have the affix active now instead of the entire bunch.