and a lack of public toilets. People are people — we generally would rather go to the bathroom in private if it's an option. Homeless people don't shit in the street because it's their first choice.
Can I? How much do you think someone who shits in the street today is willing or can afford to pay for private toilet infrastructure? I disagree with RMS about a lot of things, but I don't see how this would be solved without public spending.