Well I can certainly understand them. Based on price tgey would not be able to compete and have half decent living wages so protectionism AND subsidies is a decent strategy to maintain local production which I feel allow a country / area to not lose a lever in international negociations.
Yes it's great for the EU, but not so great for the Mercosur, is it? The EU wants them to buy products from the EU, but if the Mercosur acted the same way as the EU does with regards to agriculture, would mean they would also "protect" their industries from "unfair EU competition" and no deal can be made at all.
If you want to have commerce, you need to give some to get some. Without agriculture being included, the EU would just take and not give anything. It used to work in the colonial times, but one would hope that is behind us now.
The quotas for these products in the trade deal would have been very limited, and the opportunities for our industry far greater.
It was a small vocal minority that avoided benefit for the majority