The rates for long-run capital returns and dividends are such that they are very beneficial to owners of capital, and they like to keep it that way. The upper-middle class folks who are working have their labor and ordinary income taxed at increasingly higher marginal rates. The rich often fund demagogues who talk about handouts for the poor while ensuring that "progressive" tax rates remain high on their potential rivals who pay high labor taxes.

>1. What is your working definition of liberal(positive vs. Negative freedoms)?

Today, I think the word "liberal" means "someone who thinks that the poor should benefit at the expense of the rich, through government coercion"

>2. Income tax taxes... Income. Not labour. Ideally not discriminating between capital and labour income

Why tax income? Why not your bodyweight? Or height? Why not tax consumption? If the answer is "to punish those with high _incomes_" you are in violent agreement with the ultra-rich.