The man-made object responsible for the most deaths worldwide is the tobacco cigarette. It isn't even close.
Tobacco kills 443,000 Americans a year and 5 million people a year worldwide. This is more than the total number of people killed by cars and firearms combined. Cars kill about 32,000 Americans each year and 1.3 million people worldwide, while firearms kill about 32,000 Americans each year and "several hundred thousand" people worldwide.
100 million people were killed by tobacco in the 20th century. This is more than the death toll from World War 1 (17 million) and World War 2 (50 to 70 million) combined.
From a strictly utilitarian perspective, would there be anything to be gained by, say, starting a campaign of assassination against executives of tobacco companies?
On the other hand, if we can't ask questions like CronoDAS' on LessWrong, where the hell can we?
In all controversial questions I can think of (offhand), that problem can be sidestepped by phrasing it in less loaded terms, e.g. "group A", "group B", you get the picture.
Also has the benefit of avoiding political/mindkilling contexts when they are not inextricably linked with the question, making rational discourse easier (though a controversial framing does offer the benefit of often making the question more poignant).