Have you ever confused mental illness with indolence? I mistakenly assumed this man was a bum.
Why did you think he was a bum?
Because even though he had cancer he went around collecting bottles, plus he had greasy hair.
Just because people act in a certain way that you don't like, you should not judge them for that, or assume that they are homeless bums. You should get to know people before making assumptions about them.
So I should just not judge people when I see them?
Forming tentative impressions is OK; forming intractable opinions and judgements based on superficial details is not. Appearances often don't reflect reality.