I dont think you are missing anything. The feed points of each of the
radiating elements need to be in phase if 'broadside pattern max' is
desired.

Do you intend to build an array, or just trying to understand them?


Both. I have some FSJ1-50 that I got for the purpose.

The docs that I've seen are all pretty consistent on how it should be put
together, but I just don't understand the workings of it.

IF the coax had a VF of 1.0, then it would make sense to me.