Comment by schlauerfox

"he’d forgotten to write the bootstrap loader" He didn't load the whole program from the switches on the face, just the bootstrap that would let them feed the paper tape through the teletype/paper tape reader that was common at the time. It would take a very very long time to load the whole program by hand. See this video of a demo. https://www.youtube.com/watch?v=TxU_3dEJ2nM