@ Selene - Most organizations that help the homeless are geared to prevent situations like that. I can only remember names of the groups from my recent trip to Los Angeles, but the same things occur in the other cities, as well. L.A. Mission, for example, gives homeless people a bed. It gives them a job, doing janitorial work, secretarial work, cafeteria work, etc, to allow them to gain experience so that they are able to find a career in the future. However, they must stay clean while in this process. For 5 (not sure about the number, exactly...) months, they work away from gang situations. If they choose to go back to the street life, they are kicked out. Homeboy Industries has a similar ideology, if I remember correctly.
Also, sure, some people screwed up earlier on in their life. They made some bad choices. We have, too, though. Everyone has made mistakes. Who are we to disallow them from changing their lives? I understand that you don't want to just hand out money; that's okay. However, stating that you are unwilling to assist them at all because it's their fault that they are in the situation frustrates me. Have you ever talked to a homeless man/woman? Have they told you their story? If this has happened to you, I can almost guarantee you that they didn't end up on the streets by choice. High school drop-outs? I've come by them before. Perhaps their mom become seriously ill, and they had to obtain extra money to put food on the table. Got themselves in that situation? You have no idea what their background is. You have no idea why they made the choices they made. Home situations can screw up a person's life. Sure, we're in a wealthy society, but that doesn't mean the wealth is spread evenly. So many children end up on the streets because of where they grew up. You hear of alcoholics that end up on the streets, and you may think it's their own fault. However, when things like this come up, ask yourself this: What pushed them to become an alcoholic? What pushed them to drop out of school? What pushed them to run away from home?
Again, the whole handing out money thing, don't do that. In fact, on every trip I've been on to help the homeless, every organization says not to simply hand out money. That's not what is going to help a person get off of the streets. One-time encounters rarely impact a person enough for them to turn their life around. Like I stated earlier, there are other ways to help. Other, better ways than walking up to someone with a shopping kart and giving them $20.
TL;DR
Don't be so quick to judge.