There's an assumption that if you pay taxes, then you have no social responsibilities beyond that. It's subjective perhaps, but to me that's such a weird way to look at the world. Helping people is one of the main purposes to life, and - particularly if you're partly to blame for the problem - why wouldn't you want to help as much as you could? In this case, it'd even be partly selfish to help, as your employees would presumably be happier if they didn't have to step over homeless people on their way to work.

We can't rely on the "system" to be perfect. You can't say "As long as it's legal it's good" and you can't say "so long as I pay the tax I have to all is well." You have to develop a conscience.