Oh, I have no doubt that they came up with a valid way to explain why electrical systems were disabled.
That's not the problem. It could be a satellite EMP field, or nanites, or whatever else you want to use to explain it. The problem is that nothing they're doing
makes any damn sense. So yeah, they have an explanation for the lack of electrical systems. So why isn't everyone using steam power? Why are they able to build stills but not anything that's actually useful to humanity? Why did every single aircraft fall straight
down from the sky (while their lights were still on)? Why do the magical talismans have super awesome batteries able to activate a magical field 15 years later? <insert any other question asked throughout the thread here>?
It's the "what if?" aspect that they've screwed up royally, not the initial "how?" that started everything rolling.