You ignored

> but let's assume that you can make sheep milk in Australia that has the same properties as Greek sheep milk.

As a customer, why would I assume this? It's one thing for an Australian cheese maker to write 'feta' on their product because they think it's similar enough to the Greek cheese and another of it actually being similar.

As a customer the only way to find out would be to buy it and try it out. I don't want to have to go through the fine print on the packaging when all I want is some feta cheese for my greek salad.

For the record, I usually buy Turkish sheep's milk cheese because I like it better than feta cheese, but I very much prefer that those are clearly labelled differently so I can tell them apart.

That’s still just a property of the physical product. That’s just half the story. The important thing is keeping the production in the original region. So I want it to have the competitive advantage of the name. As a consumer I want my money to support the producers in the original location, which is easier if I know that the name means it’s produced there.

Note that zero of these arguments have anything to do with quality or whether I could even distinguish the product from one made elsewhere. That’s secondary.

I thought it was encompass in « more than the sum of its part ». The milk is core, the process is key, the conservation and timing is deceptively important.

You might feed the same breed of cow the same altitude grass, at the same season… and still end up with a different product.

But I see your point, and I think it’s a reasonable one. It’s possible to duplicate a cheese making process and be successful ( or wine: California comes to mind )

But that might be tricky, and maybe i don’t want to be disappointed so I will go with the Geographical indicators label. It’s a safe bet.

A sister response to my earlier comment bring a good point. Sometime you want to patronize a particular region for sentimental reasons.

Valid point. If the conditions in a given region actually make it impossible to replicate Greek Feta – then you just can't make Feta there.

However, it might make sense to allow some leeway to avoid unnecessary shipping. Not very relevant in Macedonia, but if an Australian gets Feta from Greece instead of a local substitute which is close enough for most customers that should be an explicit decision on their part.

In any case, you can still look at the "made in..." label to determine the product's origin.