That's far too grand a generalization for me to agree with.

And here I thought I had put in enough qualifiers to make it nearly a tautology.

It seems a quite specific statement to me. Reading liberally some qualifiers (“all else being equal” in particular can mean lots of things) this might become tautological, but I reflexively interpreted them as what I think you meant (since I didn't think you just made a useless statement).

About the justice system, you got it right. Justice systems try to correct lots of bias sources. Not only the one you mentioned, but the “own interest” problem is especially pertinent to the origin of this thread (the example of “men deciding abortion issues”).