So I guess in theory you could carve out an exception allowing nonconsensual human sacrifice on religious grounds. That seems like sort of s major loophole.
In practice, it would be deemed a fake, rather than real, religious conviction, since the religion would be too new or not have enough popular support.
…or else it would undermine state power, and so the actors in the system would be forced to change it.
Naturally, I don’t believe in pure freedom of religion.