“WTO rules will NOT apply to the EU countries we trade with because......they’re protected by the EU!”
Someone, somewhere, has hold of the wrong end of the stick here, Zacs.
Much as it would like you to think otherwise, the EU and its component nations are bound by WTO rules and tariffs when dealing with any country with whom it has no specific agreement to the contrary. If Brexit is concluded with “no deal” that will include the UK. Of course there will be initial difficulties with such an arrangement. However, other nations manage to trade with the EU perfectly well under those conditions and the UK government and UK companies will have had almost three years to prepare for such an eventuality by next March. The fact that neither has done so is scarcely a good reason to say we’d better not do it.
EU “protection” (which I prefer to see as “protectionism” – a slightly different concept) does not trump WTO rules. Similarly with aviation, there is talk that flights to or from the UK, or even passing over the UK en route to the EU, will not be permitted to fly. This again gives the impression that EU rules somehow override international agreements. Civil aviation is governed by the 1944 Chicago Convention on International Civil Aviation (most recently revised in 2006) to which all nations that are members of the UN are signatories. You can see from this summary:
https://www.skybrary.aero/index.php/Chicago_Convention
that the third, fourth and fifth “freedoms” provided by that convention relate to the prohibitions that some parties seem to think will follow a “no deal” Brexit. Whilst it is true that these freedoms are not automatic but are provided by national agreement, I believe the EU (or its member nations) will have some difficulty in unilaterally derogating from the Convention for what are purely political reasons.
The EU may well have succeeded in forcing its gullible member nations into allowing its national law to be usurped. But thusfar it has not managed a similar feat where global conventions and agreements are involved.