Everyone, but especially the working poor deserve a civilized way to get to work. Without screaming, smelly, sleeping, druggies taking up the seats. Or worse.
Bus drivers don't seem too excited to enforce the fare either. They're not exactly law enforcement; it might be dangerous and it would delay everyone else on the bus.
Honestly it’s not that big a deal if someone sleeps on the bus. Homeless, drunk, tired from work, whatever.