"But that is not what they are actually studying. They are studying climate change and its relationship to violence and make no attempt to determine if it being man-made makes any difference. It is irrelevant."
Let me try to understand your logic.
There is a situation where it is accepted by all institutes of science in the world that X is causing Y.
A study finds that Y causes Z. Quite obviously that implies that X is causing Z. But you are saying the study authors cannot mention that implication in their paper? Because if they do it's biased?
"Imagine they were studying the difference between violence in men and women and at the end of the study made some statement about the "difference between violence in black men and women", they betray an underlying bias that has nothing to do with the subject in hand."
Well that analogy has no findings and it misses a widely accepted relationship.
A better analogy would be a study which finds that respiratory disease cause an increased risk of heart attack. Now you say the authors aren't allowed to even mention the obvious implication that therefore smoking causes an increased risk of heart attack, because their study wasn't specifically about smoking. And if they do mention it then they are biased - pushing the old smoking causes respiratory diseases line to get more funding.