Active Pause is basically a "cheat", that's why it has a totally non intuitive keymapping. It stops your plane, but nothing else in the game world, so that you can work in the cockpit at your leisure, then continue on when you're done flipping switches and what not.
Regular pause is the Pause key. Totally intuitive for you, that pauses the game. Active Pause is something special, therefore something special needed to enable it.
All the tutorials refer to the default key mappings, which is the way it should be. If a user goes in and remaps commands it's on them to remember what does what. It's not the developers responsibility to waste time developing a system to help you remember custom commands.
Learn with defaults, than move on to remapping things.