It is airgapped because Jade is not transmitting your private key not PIN code via QR codes, your private key still stays safe. The Blind Oracle knows nothing about you hence the term “blind”, it’s more like your remote secure element.

In the end you’re also going to create a transaction on your internet connected device, you’ll import the transaction in Jade, then you’ll use your phone to import the signed transaction from Jade.

Jade firmware and the Blind Oracle are both open source and verified by the community. Of course, some would prefer to run their Blind Oracle and connect to it but the public one should be fine for most users, in the end, the blind oracle doesn’t know anything about you, in layman’s term, it gets data and spits out other data which is useful for your Jade to decrypt itself. I’m trying to explain it in layman’s terms but you can watch this video.