"People with biases might not like it" gives basically everyone a heckler's veto. Now I recognize that you don't actually plan to give everyone with a bias such a veto - only the people you agree with - but your stated principle is not a good one.
You're probably right that this betrays a bias of mine. And you're also probably right that this isn't a great guiding principle for decision-making in the future.
Still, if I'm interested in increasing the total number of people contributing to open source projects, I would give an issue like the use of the word "retard" a fighter's chance.
Maybe it's not worth bending on free speech in some specific cases, but there is a point where it is worth it, ie, if there are enough people in the offended audience that the chance of losing a potential contributor is nontrivial.
"Announcing "I'm offended" is basically telling the world you can't control your emotions, so everyone else should do it for you."
The ironing.
Banning thoughts and words, as you seem apt to suggest, is how we migrate away from the principles of the 1st amendment. Of course, you will be wont to tell me that a private company isnt bound by them. Indeed.
But where do we stop? It may be vogue to silence the KKK, which is pretty established for hate speech and actions. But what then? Who decides amongst us what hate speech is and isnt? How far do we go down this rabbit hole? The answer is, "We wont" from SCOTUS.
http://civilliberty.about.com/od/freespeech/tp/Hate-Speech-C...
[F]reedom of speech...," Justice William O. Douglas wrote for the 5-4 majority, is "protected against censorship or punishment, unless shown likely to produce a clear and present danger of a serious substantive evil that rises far above public inconvenience, annoyance, or unrest ... There is no room under our Constitution for a more restrictive view."