Tell me, do you think I should only get to vote with 1/100th the weight of someone who pays 100 times as many taxes as I do?
Of course not. The equality of each person's vote -- political power -- serves as one reasonable balance against highly disproportionate economic power, the latter of which naturally tips our private-property-based society in the direction of feudalism. Higher taxes on higher incomes is another balance against that economic power, and is further justified by the reasoning that the have-mores have more to lose, and therefore have a higher interest in the social order maintained by our fair-minded system of government, without which society can easily tip too far toward highly disproportionate political power exercised by the have-littles robbing the have-mores into poverty.
Now, while people who have no property, don't pay taxes and can't vote also have an interest in this system of balances, they aren't sharing any of the liability, instead serving as unchecked disturbances in the system, making them inherently unfair.