And it's not just changing culture. Over the last half century, various branches of government have also taken plenty of proactive steps to marginalize religion. Prayer in public school has been banned. Creches can no longer be set up in front of city hall. Parochial schools are forbidden from receiving public funds. The Ten Commandments can't be displayed in courtrooms. Catholic hospitals are required to cover contraceptives for their employees. Gay marriage is legal in more than a dozen states and the number is growing rapidly.
"Gay marriage" being legal doesn't marginalize "religion," just some flavors of some faiths, not all of which have made up their doctrinal minds on the subject.
Marginalizing cetain ostentatious displays of faux Christianity isn't marginalizing "religion," either, unless you define religion down to the six things your sanctimonious sister-in-law is pissed about this week. Taking a bunch of fake issues that have fuck-all to do with the actual practice of religion in this country and using incorrect assumptions about them to agree with the general wingnut position that Christianity is somehow under siege, is ... reductive, at best.
I expect this kind of half-assed shorhand from middlebrow media outlets and commentators whose audiences are just biding time until the orderly comes round with the pudding, but my standards for Mother Jones are a little bit higher.