Because without bad to coexist with good, all balance within this fragile Universe would become unstable, bringing It to and all life in the Universe to and end.
Magic H8 Ball, why does Combustible Lemon reek of death? Does he never take a shower? Why doesn't the FDA regulate his kind more? ANSWER ME!
Edit: Putting "Hate Week" at the end in this thread seems to be redundant at this point.