Why are you not against this? A vote isn't a payment in exchange for taxes. It's the mechanism by which the government represents the will of the people. How do you arrange things such that the government acts in the interests of people if it doesn't need to chase their vote? Or are you actually saying that poor people don't deserve a government that acts in their interest?

Even skipping the moral argument, there's a game theory trap here: let's say you run a government and your political enemies are on the poor side and fall into the "no vote" trap more often than your supporters. Obviously the solution to maximizing your share of the vote is to make them even poorer.