The new faith is against the old one and aims to tear things down. It doesn’t have any idea how to replace what it’s torn down. From Paul Rosenberg at freemansperspective.com:
Christianity, as people in their 60s and 70s have observed, was pushed off the public stages of the West over the past two generations. At this point, whoever speaks well of it in such places must be prepared to absorb blows.
Nonetheless, nature abhors a vacuum and just about everyone, including the most strident atheist, requires something to believe in. And so the exit of Christianity drew in new faiths, and one in particular, to replace it.
Faith, whether it be called religion, anti-religion or whatever, is a practical requirement for nearly everyone, simply because people aren’t prepared to face an overpowering universe and all the uncertainty in it as a lone individual. They require beliefs like a man requires garments in winter.
The people who pushed Christianity out of the West, however, were anti-religionists, and abysmally bad at mythology. They didn’t even try to replace the old myths until fairly recently, and poorly at that. And so their new mythology came together haphazardly. It was, in fact, confused and unclear, which gave all sorts of rehashed lunacies an opportunity to plug in.