Does it need an explanation or a comparison though? ACTA is not SFB is not FC. Sure they're all in the SFU, but they're not the same game.
If people are persistant though, you could think of it as: the only special action you're allowed to use while cloaked would be to reload or decloak, so after the first turn of engaging the cloak, you could think of each turn after that as a 'maintain cloak' special action, requiring power to continue to go into the cloaks.
The critical in question, crew level 4, involves multiple fires, localized decompression, and secondary explosions as the 'effect' on the critical table. Even if the crew itself isn't needed to direct or maintain the energy flow to the system, power must be disrupted somewhere in order for the ship to gain no bonus from any special action. Power isn't going where it needs to go for everything to keep working.
Its suffecient enough reasoning for me, and this is the first ACTA as well as the first SFU game for me so I'm not much rooted in what both universes have done in the past. Comparing apples and oranges.