Rob Kaufman believes that the phrase income inequality indirectly suggests that everyone should all have an equal amount of money, which is something that a kindergartner would say.
Obviously, it does not make sense to suggest that everyone should have an exactly equal amount of income. Many skills must be learned, many trades must be studied, and not all workers are of equal value. Hard work does not entitle you to whatever you want. Hard work entitles you only to what you negotiated, and what you earned as a result of that agreement.