> Sometimes you're just looking to get to work without having to put on a show of saving the world.
Agreed. You do not need to be in "Save the World!" mode at all times.
> Homelessness is a problem for the homeless. Homeless people sleeping on the buses are a problem for commuters.
Disagreed. Homelessness is a problem for everyone. While homeless people exist, they will necessarily cause problems for the rest of the society. Here are my takes on it:
1. Homelessness is a spot in society. If you take all the non-homeless people in your community and move to a brand new piece of land that is completely isolated from the rest of the world, new homeless people will appear. This is because being homeless is inherent to certain societal setups and the percentage of homeless population can be determined "at compile time" via static analysis of the rules and initial state of the society.
2. The homeless/poor/hungry are a problem for everyone and everyone pays the cost. It is rarely direct (e.g.: not everyone gets mugged), but often indirect. For example, your car or renter's or homeowner's insurance is higher. You have to pay for a security guard in your apartment building. You have to pay for your bus ticket. You have to buy a more expensive bike chain.
3. Given #1 and #2, it is in everyone's best interest to solve the problems of homelessness/poverty/hunger.
I am not saying that we should drop everything and not stop until it is solved. I am saying that it should be a pretty high priority and that the question of whether we tackle it should be "yes".