Why does the Court of Justice of the European Union allow for exceptions to free movement of goods outside of those laid down in Article 36 TFEU?

Article 36 of the Treaty on the Functioning of the European Union (TFEU) allows for certain exceptions to the free movement of goods within the EU, stating that quantitative restrictions on imports and exports can be justified on the following grounds: public morality, public policy, public security, protection of human, animal, and plant health, the protection of national treasures having artistic, historic or archaeological value, and the protection of industrial or commercial property. However, these exceptions must not be used as a means of arbitrary discrimination or as a disguised restriction on trade between member states. The Court of Justice of the European Union (CJEU, formerly known as the European Court of Justice) has indeed recognized additional exceptions to the free movement of goods, beyond those listed in Article 36 TFEU. Through case law, the Court has developed the concept of "mandatory requirements" or "imperative requirements," also known as the "rule of reason." This concept recognizes that certain national measures restricting the free movement of goods can be justified if the measure: 1. Pursues a legitimate objective in the public interest; 2. Is necessary to achieve the objective; 3. Is suitable for achieving the objective; and 4. Does not go beyond what is necessary to achieve the objective. Some of the exceptions recognized by the CJEU under the "mandatory requirements" doctrine include: 1. Environmental protection: In the case of Commission v Denmark (Case 302/86), the Court allowed an exception for a Danish law that banned the use of non-returnable beverage containers in order to protect the environment and reduce waste. 2. Fair trading and consumer protection: In the case of Commission v Belgium (Case 21/84), the Court accepted an exception for a Belgian law that required margarine to be sold in cube-shaped packaging in order to prevent false representations of the product. 3. Cultural protection: In the case of Caixa Bank v France (Case 442/02), the Court allowed an exception for a French law that restricted the availability of foreign-language television channels to protect the French language and culture. 4. Road safety: In the case of Commission v Italy (Case 110/05), the Court accepted an exception for an Italian law that required truck engines to have a maximum noise level to ensure road safety. 5. Protection of public health: In the case of Henn and Darby (Case 34/79), the Court upheld the restriction on importing certain publications from other member states that were considered obscene, as the purpose was to protect public health and morals. It is worth noting that these exceptions recognized by the CJEU are subject to a proportionality test to ensure that they do not go beyond what is necessary to achieve the legitimate objective pursued. The Court has also reiterated that these exceptions must not be applied in a manner that would create arbitrary discrimination or a disguised restriction on trade between member states. In conclusion, while Article 36 TFEU provides the main legal basis for exceptions to the free movement of goods, the CJEU has recognized additional exceptions through case law, under the doctrine of "mandatory requirements" or "imperative requirements." These exceptions must be justified based on a legitimate public interest, meet the proportionality test, and must not be used to create arbitrary discrimination or disguised restrictions on trade between member states.