What role does transport play in the climate assessment? Why does product X from Switzerland have just as many stars as product Y from abroad?

Transport plays a minor role in carbon footprints, unless the product has been transported by air. The decisive factors are agricultural production, and in the case of animal products husbandry and feeding, as well as fertilisation and the use of pesticides. The same production methods are used abroad as in Switzerland, meaning that the carbon footprint does not change by very much.