Nothing is so black and white. If you point out that others are engaging in bad behaviour, then it makes that bad behaviour look less bad.
That depends entirely on the ethics of the looker, but are you really saying that people would engage in fewer acts of bad behavior if other people didn't point them out when they did?
What do you mean with the "nothing is so black and white" cliché in this context? The psychological reaction of onlookers has nothing to do with an action being ethical or not.
I had the opposite reaction, that the poster was implying the HN zeitgeist should be raking these companies over the coals also.