Our personal obligation to help those who are less blessed than we are is not relieved merely because we pay taxes, and especially not because we vote for others to pay higher taxes to as to benefit the poor. Our obligations are not just monetary, and not just for pro forma purposes. Instead, they are supposed to be mindful and conscious. We should always seek to help other people by giving what matters most.
Indeed, even interpersonal gifts are best with they have been carefully considered and evaluated. We know the difference between a random gift and something that shows real thought has been invested.
This might help explain why the Torah requires every sacrificed animal to be absent any visible blemishes. G-d is not hungry, and He is not offended by smaller or weaker offerings. But He clearly does want us to always act with consideration and care. And if we are commanded to only offer animals that have no blemishes, then it forces us to carefully examine the animal, forces us to invest personal time and consideration in a gift which, if we are easily able to afford offering the animal, we might otherwise offer up without a second thought, sort of like ticking the boxes for the commandment in question.
This rebounds nicely: the purpose of an offering is not because G-d is hungry. The offering is to help the offeror grow, to move past an event or action in their life, and to focus on positive directions. So requiring the offering to be mindfully inspected in order to ensure that it makes the grade is a way to ensure that the person offering the animal is personally invested in the process: they are interested in growing.
[an @iwe and @susanquinn work]
P.S. The commandment to avoid blemishes does not include birds. Why not? Is it because birds are given by the poor, and as the cost is meaningful for them in itself, we do not wish to burden them further? Or is there a better reason?