WARNING!
SOURCES ON GITHUB WILL NOT BE PART OF THE ORIGINAL CHAIN.
THE GENESIS BLOCK WAS NOT INCLUDED THERE.
Wait the official binaries and sources. That is not LeviarCoin official chain.
Am I interpreting this correctly that you can't build the wallet from the source code in the github repository because it doesn't include the genesis block.
If so, why?

This is old, they have released the real source now.
Check leviarcoin homepage
https://leviarcoin.org/project at the bottom, they have a link to github.