Why does one belief get respect when other, identical ones do not?

[iris27]

7. In parts, it is, slowly. (Too slowly for many of us.)

Already, the parts about owning slaves, and about blacks and Jews not deserving equal rights are discredited, and anyone who actually believes them is rightly called racist and considered a white supremacist on par with Stormfront. This was not the case just a generation or two ago, when anti-segregation arguments often used biblical justifications. And the wheel is turning with respect to gay rights, too. Within our lifetimes, "all good Christians" will think it is terrible to use the bible to justify hatred of gays.

But, sadly, the book "as a whole" will continue to be revered as the basis of a popular faith.

I appreciate Christianity's adaptability on the one hand, because it means the morality of a majority-Christian society can still progress and "bend toward justice" and MLK would say. (Unlike certain majority-Muslim countries that still practice a Dark Ages morality, enforced by "religious police".) However, it is that very adaptability that ensures the continuation of Christianity as a faith that can be embraced and practiced by largely modern people.