Orphans and Their Situation with Abusers

You're not the sharpest tool in the shed, are ya? This joke is about how orphans can't report being abused because they don't have parents. The humor comes from the dark irony and the fact that it's a taboo topic, using a word like "pedos". It plays on the vulnerability of orphans and the lack of recourse they might have when bad things happen. It's a bit shocking, but that's the point.