When you build a community you're creating a culture. That culture will be about more than the code, the modules, or the language. The people you draw in will have their own biases and behaviors that impact the kinds of people you continue to draw as you grow.
Cultures will naturally fight behavior that is divisive. That is, behavior that is divisive to the established members of that community. As a community grows larger it is harder and harder to change what the culture finds acceptable because changing it, even if it is inclusive in nature, is disturbing and divisive to existing membership. Fighting for change in established cultures means dealing with a lot of dismissive language and attacks for the "tone" of your argument.
That is why it is so important that a culture becomes comfortable with aggressively fighting exclusionary behavior. While it is certainly more beneficial to make pro-active steps to increase diversity we cannot be dismissive of the effect that passionate reactions to poor behavior have.
More important than the actors themselves this sets the tone for acceptable behavior in the observers. Spectators come to recognize what is and is not acceptable behavior. Most newcomers will mimic what they see and observe as good behavior and those unwilling to bend to the culture won't join by self-selection. It may sound harsh but this self-selection is an inevitability, you will either self-select out people comfortable with a dominating gender or race or by including them people of more diverse backgrounds will exclude themselves.
It's not enough to simply state your values, you must live up to them. You cannot accept behavior, or people unwilling to change behavior, that is racist, homophobic, or gender biased. While certain behaviors are more serious or offensive than others the more uncompromising the culture is to even the smallest exclusionary practice the more inclusive it will be of increased diversity in the long term. You want people uncompromising and unaccepting of exclusive practices because they are cultural anti-bodies to those joining that would actively hinder diversity.
We've worked hard in node to make it clear what is not acceptable. This applies to everyone, the culture demands it from not only new members but the established leaders. If you're thinking of joining the node community you should recognize and accept this culture and know that we don't accept exclusionary behavior and we never will.
@mikeal, thank you for taking the time to write a thought out reply.
I think, though, that the questions I raised (and their underlying concerns) are still germane given the realities of our day. Namely, that in the age of social media the line between private and public discourse is often blurry at best.
Consider again the hypothetical developer. Suppose she were to engage in a lively debate concerning a sensitive topic – such as the one suggested before, or any other – by way of her twitter feed, or a facebook backed comments section, or google plus, or gist comments, or whatever. It would only be a matter of time before someone tied her comments back to her persona within her online developer community, at the office, her meetup group/s, etc. I don't believe this is too hypothetical.
Then, faced with the community mounting an "unacceptance" campaign against her, she would have at best a few options: recant her positions and make apologies for words said in the past; stick her ground and suffer the consequences; keep her mouth shut in the first place.
With respect to deeply held beliefs, all three are non-trivial matters, but it would partly depend on the scale of the consequences. If it were simply a matter of being on the receiving end of some sharp words, perhaps being persona non grata for a time, that would be one thing. If instead she were to face the loss of her ability to participate in and contribute to open source projects/communities, or even risk her ability to keep or find employment, that would be another thing altogether.
And that brings the matter back around to the question of the ethical limits of an "unnaceptance" policy within developer communities, workplaces, etc. While I have no problem generally with the idea that behaviors and words which (or persons who) are discriminatory or divisive should be discouraged, I have to wonder about how the offending actions and words are to be judged, and the limits of exclusion with respect to those who express ideas that are unpopular. I don't think any of us want to create atmospheres wherein our peers are genuinely afraid to speak about their personal beliefs for fear of being shunned, losing their commit privileges, or their jobs.