I don't disagree.
Nevertheless, please find some research on the mind-altering effects of blue jeans (particularly on judgement), and then get back to me.
What other evidence would the other poster require, other than seeing how many murderers wear blue jeans relative to the population at large? Once again, I claim that correlation does not equal causation. The fact that murderers use drugs doesn't prove drugs induce people to murder any more than the fact that murderers wear jeans proves that jeans induce people to murder.
You are missing the point. We know that drugs cause people to make stupid choices. Therefore we can deduce that if a person commits a murder while under the influence of drugs, the drugs may have played a role in that behavior, especially if the person does not have a history of murdering people when he wasn't using. This is not the same thing as saying that a guy who normally wears khakis, but happens to be wearing bluejeans the afternoon he walks in on his wife and the UPS guy was in any way influenced by his choice of apparel.
Put it another way: I suspect (no I know for a fact without being told) that if we were able to remove drugs and alcohol from society, the murder rate would go down.