When did it become acceptable to joke about 9/11?

For many people in their late teens and early twenties, 9/11 belongs to history, not memory. (Picture: Getty/Metro)Search the darker corners of the internet and you’ll find jokes about almost any major event almost immediately. Yet some tragedies seem, at least for a while, too enormous, too raw or too culturally significant to become punchlines.For many people in their late teens and early twenties, 9/11 belongs to history, not memory.Many were yea