There's also: http://news.ycombinator.com/item?id=589200
I only mention these two links because I've started trying to apply them to myself, and they seem to be helping. When people react badly, I first think "it's not me", "this is a one-off" and "it's only in this specific circumstance". That helps me to be "liberal in how I listen" by defusing my anger/judgmentalism. Then I try to be "strict in how I speak" by being factual (this is hard, but I can do it) and warmly/kindly (I'm not so good at this part - but that's how I'd like them and me to be.)
BTW: I think you make your point about consumers very clear in the above - it wasn't as clear before. hmmmm... maybe explicitly mentioning "in general" (as you do here) is a shortcut to avoiding people taking things personally, if one senses they might. I recall in Ben Franklin's autobiography, he reinvented his whole style of expression to be less confrontation, to "it may be so", "it appears to be" and such like, as he was getting in too many duels (a.k.a. flame wars?)