The meaning and implications associated with words frequently change. The words that modern day feminists use, equality etc, are similar to those used when the movement started in 1960 but the meanings are almost the complete opposite.
This is often the result of poor education, and often political agendas. The modern perception of income inequality compared to the classical perception is a particularly good example.
A classical view of income equality is the view that everyone has the freedom to pursue what they are good at and work hard at it. It is man’s essential right to have the freedom to guide his own destiny to reach their full potential. But the fact of the matter is this ability to choose any variety of options will not always result in the same outcome. If you were to choose to spend the rest of your life building snowmen you probably wouldn’t receive the same financial rewards and results if you had chosen to be a computer scientist.
The classical viewpoint saw income inequality is a good thing because everyone is free to pursue a path that they think uses their best talents, whether that be accounting, teaching, or dancing. This makes life enjoyable. We all have different strengths and weaknesses which makes this indeed a form of inequality.
At its core, classical income inequality does not view disparities in citizens earnings as bad. But rather the result of choices.