Due to human nature, income equality is not fair.
For example, take three people working the same job and making the same pay. One of the workers sees the job as an opportunity to succeed and be promoted. The second worker sees the job as an end job, and he intends to do just what he needs to do to keep the job. Then there is the third worker who sees the job as a burden, so he does as little on the job as he can get away with.
To pay these three workers the same pay would completely defy logic. The first worker should be paid the highest because he is doing more than expected on the job. The second worker should be paid the next lowest because he is contributing less. The third worker should be fired and paid nothing.
To be fair, I think that income should be earned, not just distributed.