Even if you “do” know they’re drug addicts, what most people don’t seem to know is that most addicts and panhandlers are mentally ill.

Ironic that you used this example, because most people truly are ignorant (ie; lacking knowledge) of the plight of the homeless.

I read a story of someone who yells “get a job” at homeless people. That’s true ignorance. Someone who is mentally ill and lacks access to a shower or clean clothing can’t just “get a job” — it’s not that simple.