I've always liked the analogy to Barry Bonds for this kind of thing. There's a famous quote out there that goes something like, you can't point to any specific

I've always liked the analogy to Barry Bonds for this kind of thing. There's a famous quote out there that goes something like, you can't point to any specific home run and say "he hit that one because of steroids," but you can be sure he hit more home runs because of them. I think that kind of reasoning applies equally here. You can't necessarily point to bias for any given case (or at least not this one), but that doesn't mean the bias isn't there.