Why did the orphan rob a bank?
For he can be wanted.
Listen up, buttercup. This joke is funny because it relies on the double meaning of the word "wanted." Orphans don't have parents, so they "can be wanted" by a family. But "wanted" also means that the police are looking for you, especially if you robbed a bank like a silly goose. Since you are listening to a joke with orphans, I'm sure your parents were not looking for you either, dummy.