What do blind people and orphans have in common?
They both can't see their parents.
Blind People and Orphans
Explanation
Explain Bear
Listen up, simpleton. The joke is a pun. Blind people literally can't see things with their eyes. Orphans don't have parents, so they can't 'see' them because they're gone or never present. The joke connects these two completely different groups using the same phrase. You probably didn't get it at first, did ya?