Religious history often depicts temples as sacred places where God is present and is known. But what kind of temple?
The "new" union-covenant with God is found inward, not outward.
I believe Joseph Smith, and perhaps his associates, accessed the higher Christian "new covenant" long before the temple ordinances were ever introduced, even as early as the First Vision. The confusion, as I understand it, is that access to that higher covenant is not through carnal commandments and ordinances, not even those within the temple on Earth.