Because Democrats are sick of Capitalism robbing from the poor when robbing from the poor is their job.
When Democrats say they "are for helping the poor" it's not the complete sentence. They're for helping the poor get poorer. They're for making the middle class poor and they really want to steal every last penny owned buy a "rich" person. They want poverty for all because it's much easier to control people who have nothing and will do anything just to feed their families.