We weren't kept completely in the dark about our estranged transhuman cousins, but I think there's been a concerted generational effort to repress those memories.
Maybe our ancestors were afraid we'd see some appeal in the idea of accelerating our own evolution if we learned more about Homo deus.
If so, that seems silly, because there are kiloparsecs between us and the refined xenomaterial they needed to do it.
Historical archives say the Element War was fought over divergent ideas about how to deal with our polluted biosphere and dwindling resources.
Our ancestors in the Terran Federation thought they'd finally found a clean source of power for their grand geoengineering schemes to hack and repair the planet.
The United Republics of Earth wanted to hack themselves using that same power, and survive by becoming more than human.
Neither side was right.