Jokes that need a smaller kid as the punchline aren’t comedy. They’re a hit and run with a laugh track.

A joke that needs someone smaller to work is not really a joke; it is a way of showing the room where you stand, with a laugh attached for cover. The laugh makes it hard to object to, because anyone who does becomes the one who cannot take it. The person on the receiving end carries it long after the room has moved on.

When you catch yourself reaching for that kind of line, notice who pays for it. If you are in the room when someone else does it, not laughing is already something, and saying so out loud is more.