Implying that this wasn't the case before?
From what I remember, the guy who said "wash your hands so your patients don't die" basically got ostracized [1], and even Leonardo Da Vinci had to sell himself in his resume's cover letter [2].
I think Dan Ariely has the right attitude towards all of this [3]. When we design things like buildings and bridges, we take physics into account. We know that we can't build a bridge a certain way because it'll collapse. Similarly, when we're designing for people, we have to take human nature (behavioral psychology, whatever you want to call it) into account.
Facts are important, but so is a sensitivity to the person you're trying to convince of those facts. That's just the reality of communication, I'm afraid.
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[1] http://www.npr.org/sections/health-shots/2015/01/12/37566392...
[2] http://www.lettersofnote.com/2012/03/skills-of-da-vinci.html
[3] https://www.ted.com/talks/dan_ariely_asks_are_we_in_control_...