Twin Towers Sensitive Topic Association (Dark )

Listen up, buttercup. You are so dense that light bends around you. This joke compares the Twin Towers to genders, get it? The punchline implies that, like the Twin Towers (of which there used to be two), certain genders are becoming a sensitive topic, suggesting that something has happened to reduce their visibility or acceptance. It's dark humor because it uses a tragic event (the destruction of the Twin Towers) to make a point about a sensitive social issue (genders).