Recently I was reminded of that old saying, and why it matters.
For quite a while now, the common social skills have been devalued in programming. It's become almost our version of machismo, this blunt commentary about others' work.
Frankly, it's stupid. Nobody is immune to the discomfort of having their work denigrated or dismissed. I mean, why are we not promoting at least a modicum of civility? How hard is it to rephrase from "This code sucks" to "This code needs some cleanup" ?
Some will no doubt claim that it's meaningless fluff; a waste of precious time to consider feelings. But it's not - there is no truly egoless programming - if there were, we could not be as good as we wish to be, because only through the personal pride of doing a job well can we have good code, and even if we fail, we are not helped by someone else being rude in their discussion of the code.
This is not to say we should not mention failings in code we review - but we should be mindful of the impact of our words. If you are rude to a coworker, you risk s/he will not hear your comment for the tone - they will get angry at your tone or wording, and resist the discussion because they will perceive you as hostile, instead of helpful.