Depending on a setting being disabled thats more than likely on by default isn't much comfort. Most people won't know about or look for those kinds of settings, especially with the deceptive descriptions often used for features like these.
To be clear, I don't use these devices either; I'm just concerned for those that don't know any better.
The verification still needs one of the devices listed in my post to be active on your wifi to allow the setup and communication.
Yes, that's what I said; your amazon devices are giving away your wifi info to new devices. As in once you've allowed an amazon device onto your network, any new device can add itself to that network via your existing device without your input.
This happens before the new device has authenticated into your amazon account as it doesn't yet have an internet connection (ie before its proven to be your device and not say a neighbours) and before you manually provide authentication for your wifi. Hence the 'with 0 auth'.
The auth is likely done by device to device handshake. Its just that there isn't a human involved.
A handshake between a device you own but have little control over and a device you've never seen before, may not have physical access too, and that could have been compromised before requesting your info. Great.
I'm not saying they're beaming it out in plain text for all to read; just that they'll give your info to a device you may not even be aware of let alone own or have any control over. That device may be a stock Amazon device, or it could be something more malicious.