Consumer always buy the same product from the seller that offers a lower price.
Developing countries have to engage in international trade to develop their industries, provide employment for their population, and earn revenue to fulfill their import requirements. Developed nations have a higher level of consumption while citizens of developing nations usually save more than they consume. The higher income of people in developed nations also makes it possible for them to consume more and afford to buy a large number of products that would not sell in the developing nations that produce them.
While developing nations can produce products for consumers in developed nations at a price lower than what industries within developed nations can produce, importing goods is not beneficial for the industries in developed nations, for example it increases unemployment.
To tackle this, heavy tariffs are imposed on goods being imported by developed nations to make the prices similar to that of products produced by local industries. Many of these are considered unfair by developing nations as this decreases or in several cases eliminates the advantage they have. Developing nations cannot stop engaging in international trade as it is necessary for their economic development, and some tariffs that have to be dealt with by them can in many ways be considered as extremely unfair.