Orphans can't play poker because they don't know what a full house is.
Why are you making jokes about orphans?
Because it's funny to make fun of kids who won't find a home.
What you're saying is hurtful and inconsiderate to orphans. Many orphans do get adopted and achieve a loving and happy family life. You should consider volunteering in an orphanage and learning more about the process before making such hurtful jokes.