I'm an atheist as well, and I generally agree with you, it's the government's role. But in the here and now, that particular stance doesn't help undocumented people, and I know that people throughout West Phoenix rely on the packages they send out. There are people in our district taking the packages from the food bank and delivering them to less mobile families. Our families are in a food desert and taking public trans is like maybe a lesser form of Russian Roulette. Plus, that can be hard for a single mother of four to make happen. I'm guessing you have a decent sized undocumented population in the Denver area, and they'll take it however they can get it.
Religions organize around their churches and charities. Secular people organize around their government. I think we should strive for the day that religious charities are superfluous because the government by and for the people takes care of its people, but we're not there yet.