The State does not have the right to pass laws that support this religion or that.
But citizens have every right to want the State to pass laws based on their beliefs. Regardless of whether those beliefs are religious in origin - the ballot box doesn't care. Given that we are a democratic country, those citizens may succeed. If the laws do not promote one religion over another, then those laws pass the Establishment Clause. Regardless of their origins.
It is rank hypocrisy to be against this when it comes to the pro-life movement but to have been for it when religious leaders like Martin Luther King were for civil rights. (And I say this as a pro-choice atheist.)
Cheers,
Ben