You aren't duty-bound to help, no, but you only dig the hole that both you and those you deem to have failed solely from "bad choices" as you put it, by leaving them to their own devices in a society that requires money to get money, which is often the case in america. Other factors like race and sex also contribute, but I have a feeling that is not an argument I will win with you.

 By withholding the financial stability children need to grow up in to be productive, above-the-belt producers of value to the society they live in, you make a short personal gain at the expense of an overall loss of wealth, because you don't live on the frontier with a manifest destiny waiting for you, if only big government got out of the way. The fact is that you live in a collective of many millions of people, in an age where manual labor is obsolete, and the only way forward to go to college, join a trade school, or join the military. Obsolete ideas should be left behind us, where they belong, because the world we live in is not even recognizable to the one we came from just decades ago