No one should feel like they must respect beliefs that devalue their person.
This does not say that project participants cannot hold such beliefs; that is an untenable requirement for a project involving people from many countries and cultures. But such beliefs need to stay outside things like project mailing lists workplace conversations, and so forth.
And being a member of a religion isn't always a choice, being that usually you're born into it and your name identifies you as such.
Particular expressions of dislike may be choices, but the underlying feeling is not.
You're right and we're wrong!!
(Am I doing it right?)
Consider how absurd you would sound if you were suggesting that the zeitgeist on racial or gender equality was an unchangeable constant, making discussion of racism and sexism futile.
But it was never because of random debates on the internet.
Ridiculing is fine. Freedom of speech ensures religious people the right to practice their religion; it ensures non-religious people the right to ridicule and mock religion. It ensures Eich's right to speak out against the civil rights of an oppressed minority. It ensures our right to ridicule him mercilessly for doing so.
If not, then I don't see how you could possibly object to me calling a spade a spade.