No reason for different tax rates in the first place. This is just another example of the rich controlling policies that benefit them most.
ALL income should be taxed at the same, steeply progressive rates. That is the fairest way to tax, without exception. I have yet to hear a compelling argument that would justify favorable tax treatment for unearned income.
Of course, there IS an argument that unearned income should be offset by some sort of inflation factor (and earned income, too, if it’s not adjusted by inflation…a COLA of some sort). We can work on that while reforming our tax code in a way that would benefit the greatest possible number of people in the greatest possible way.