>> If homeless people on buses are a problem where you live, that has nothing to do with public transport in general.

When you hear of people being aggressive, high, inconsiderate, or here in Portland two people had their throats slit on the light rail recently near my house, it makes the public not feel comfortable using the public transportation. Since it's called public transportation and these things effect the public and the transportation, it actually has a lot to do with the public transportation.