It is simply difficult to hide. You can just go and look at the infrastructure, after all. I bet almost all the information is from OpenStreetmaps, and people just walked around and added all the power lines, substations and powerplants they saw by hand.

And sure, you can bury the cables, or you can try keeping the output of your powerplants secret. But then the infrastructure nerds (or foreign spies) just count coal hopper railway cars per day and analyze cooling tower dimensions.