The same reason you cannot use someone else trademark even if you use the same formula. Origin guarantees are just collective trademarks for small producers.

Moreover quality of the product is not always the only reason to buy a product (see fair trade, organic product, religious belief ...)

In this particular case, as with the Champagne example, the name of the product indicates its origin. Bleu d'Auvergne means "Blue from Auvergne" (a region in France), where blue is short for "blue cheese".

If someone outside of France (Auvergne, more specifically) can concoct a product with similar quality, let them label and market it under their own name.

If you fork an open source project, wouldn't it be convenient to come up with a new name for your project?

Food is not like building a car in a factory. It's not a formula like chemistry.

The milk matter, cereal matter, where cow live matter. The whole supply chain. it's really difficult/impossibile to replicate that.

You can have something similar, but call it with the generic name.

In Italy you can get really good food everywhere. But i can assure you, you can feel the difference between location. For that we get DOC, DOP to certify location, tradition, etc.

Can only speak for myself, but as there is no really objective way to measure that kind of equivalence, we as consumers are left with the rather blunt tools of traditions and establishing brands when it comes to food. Some of the product types which are protected are several hundred years old, predating all trademark laws which would otherwise have had a similar effect.

There are also some products in EU which are sold as '<something something> style <fooditem> because of the reason you state, but with that said: They rarely reach the quality of the 'real deal'. Apparently it is not very easy to create similar quality products?

If you take for instance "Champagne" - you might have an equivalent product but it's not "Champagne" unless it comes from the Champagne region of France. Yet alternative sparkling whites such as "Prosecco" (Italy), "Cava" (Spain) and "Cristal" (US) seem to do quite well. If you have a good enough product, you shouldn't have any need to claim equivalence with another regional variety.

The thing is, that's impossible. If you try to make Comté in the US, it would not taste the same and thus would be a scam.

That someone can call it the same - Cheese just like France but produced somewhere.

It is about representing the right information.

Much of the taste of food comes from inputs.

Even the water can make a significant difference. The animals producing the meat will influence taste depending on their life and what they're eating. It's reasonable that a regional product will turn out markedly different to the same recipe in a completely different environment.

It's reasonable to want the product as intended, not what it becomes after a series of shortcuts and cost savings to produce ostensibly the "same" product.

It's only heavily industrialised foods where this starts not to matter, mainly as it becomes so disntaced from those inputs.

They can label it as made the same way. They can do comparative marketing - 'we use the same techniques but better ingredients, our product is better'.

What they can't do is pretend their product is the actual traditional product from some other geographical location.

There seems like no possible way that can be detrimental to consumers?

Cheese is actually a tricky example. Cheeses produced outside of their origin geo tend to have somewhat different microbiomes and, therefore, somewhat different tastes and other characteristics. See, for example, this episode of Gastropod: https://gastropod.com/say-cheese-2/

I'm by no means an extremist on the topic. I think it would be pretty silly at this point to say that only Cheddar from Cheddar, England could be labeled as such. But origin naming rules aren't silly either.