That is the problem. They start from a false premise. There is no such thing as universal equity of outcome and it is impossible to achieve even with great oppression of those who are naturally better off than another. The qualities of resources available to different classes will always vary. Without stratification and differentiation progress is slowed especially in improving the livelihood of the poor. Today the left judge equity in terms that are impossible to achieve and would require the destruction and oppression of the most innovative, productive, and capable citizens. We saw how well this worked out in the now defunct Soviet Union.
We would not have a tenth of the technology and progress had the govt been the sole source of “innovation”.