As the goal of tax includes raising revenue and a sort of...

As the goal of tax includes raising revenue and a sort of protection to local producers. For items such as IF, there are a huge potential market especially for China. Thus the elasticity of demand is inelastic, don't you see that even A2 IF charges a premium price, the sales remains. Such high demand imported goods are supposed to be taxed more heavily comparing to elastic goods.

However, the situation in China is complication. In a normal situation, China's local producer should be able to produce and compete with foreign brands but everyone knows how bad the local products are. IMO this is the reason why they are willing to 'temporarily'(?) decrease the import tax to 0, as a compensation.