On #1: in my experience the Apple reviewers are intelligent and capable people. However they are mostly non-technical.
This is incredibly frustrating because while they are strict at enforcing policy, they sometimes let things through or block things for what seems like completely arbitrary reasons. So these virus scanner apps may be in complete accordance with policy — and they let them through. But then a well-meaning app may want to do something interesting, and because it's against policy they block it.
However for developers who want to create good iOS experiences, App review will call you to keep you updated, they will take the time to consult with engineers on your behalf, and they will even advocate for your cause internally (which can sometimes, and recently for me, result in actual policy changes at Apple).
I expect Apple will soon be refunding customers of these scam virus scanner apps, and the review team will be updated with guidance to reject such apps in the future.
I find them to be hit or miss. I've had things rejected that were just simply not in violation of the rules. I think sometimes they just get a memo or something about a specific section of the guidelines and they take it too far. I've had to take things out of my apps that are 100% within the guidelines just because I got a reviewer that didn't understand what was going on.
This is incredibly frustrating because while they are strict at enforcing policy, they sometimes let things through or block things for what seems like completely arbitrary reasons. So these virus scanner apps may be in complete accordance with policy — and they let them through. But then a well-meaning app may want to do something interesting, and because it's against policy they block it.
However for developers who want to create good iOS experiences, App review will call you to keep you updated, they will take the time to consult with engineers on your behalf, and they will even advocate for your cause internally (which can sometimes, and recently for me, result in actual policy changes at Apple).
I expect Apple will soon be refunding customers of these scam virus scanner apps, and the review team will be updated with guidance to reject such apps in the future.