I think what you're missing is: VGA was designed in the era when this was A Thing™. Monochrome/NTSC/CGA/EGA/VGA displays are all about "bit banging," sending signals at the right time. If you can send 1's and 0's faster than the analog reception can update, you can "fake" voltage potentials. I say "fake" because that was actually a way to do it before digital-to-analog converters were easy to implement. Today, we can easily produce chips custom for the purpose; however, "in the beginning" it was really just all about timing.
The witchcraft for me was the fact that while older cards used bit-banging to get signals out the door, it was generally designed with a specific purpose (thus specific timings). If you can get access to the underlying timing control, it [opens a whole new world that will surprise people today](https://www.youtube.com/watch?v=-xJZ9I4iqg8).