Do you know why you never mess with an orphan?
Because they’ve got guardians!
Listen up, buttercup. This joke works because it's a play on words. You see, orphans don't have parents, but they have "guardians" looking after them. The joke twists this by implying they have a bunch of tough protectors, like the movie, "Guardians of the Galaxy." You probably think that is the best movie of all time, just like all the other simpletons.