Whats small, black, and knocks on glass? A baby in an oven.
Are you mocking terror attack victims?
No. But it's funny because oven is a major cooking equipment which is used to cook food and you can put a baby there and turn on the fire so that baby cooks and dies. So it's funny.
Accidents happen and babies are fragile. Joking about killing babies could harm people who have lost a baby in such an accident.