@Augustus - You bring up several interesting ideas and questions:
1 - implicit bias
2 - proving causality
3 - outward effects of subconscious beliefs / effects on behavior
4 - rationalizing
1 - I suspect implicit bias is a real thing, but I don't think my argument depends on it.
2 - As for proving causality, I agree that that's difficult. That said, most of the world's most successful and profitable companies spend billions and billions (perhaps TRILLIONS?), of money each year on various forms of advertising and marketing. Huge, profitable companies like Google base all of their income on advertising and marketing dollars spent by other companies. All of these dollars are spent because it works.
And what we see used in advertising and marketing are the same ideas: repetition and emotions.
3 & 4 - Have you read "Thinking, Fast and Slow"? I would agree that the order in which we react is:
first: subconscious reaction or intuition
second: rationalization sometimes or some conscious overriding of the subconscious
So, we see a person that our subconscious is suspicious of, then our mind goes into override mode, to defeat or counter the fast intuition. This takes a lot of brain glucose. This is hard to maintain. All manner of stress is created if this kind of event happens a lot. In the worst cases people can get PTSD. So, if you're well rested you can fight your subconscious. But if you're tired or stressed, it's much harder to do so.
(I know I've oversimplified here, but I think this is largely correct.)