You know this breaks my heart as well. When I worked downtown in the city I saw so many homeless people. We even tried to help a few but some just don't want any help. I gave food as well, some was rejected. So many different reasons for each individual. Mental health, drug use, alcohol, PTSD with veterans. But you're right, the elderly shouldn't be left to the streets for any reason, I don't think any of us would allow our parents to face that..
I am always intrigued by those who ignore them. I wonder what do they tell themselves - that it can't happen to them? The wheel is turning and anyone can witness a misfortunate event that can place him right next to those homeless people that were looked down at!