There are three main forms of power a country has internationally: military, economic and soft power. The latter is the power over minds or the power of propaganda.
Soft power works by, for example, showing your country as attractive for its ideals, lifestyle, freedoms or opportunities for economic prosperity. People in other countries see these and demand the same sort of things in their own country. In this way ideas and values and social norms are spread from one country to another.
But what happens when the people in the other country have an economy that is so weakened that it cannot offer those things, or are in a failed state where the government has been weakened from outside or broken by war? In these cases, the citizens see attractiveness of the other country and no opportunity to achieve this at home. They then become economic migrants.
When the first country, the attractive one, does not want those people it attracted to its shores, then a problem ensues about what to do with those “illegal migrants” or whatever term is used to brand them as ‘bad’ and unwanted people.
The solution is to help the countries they came from provide the same sort of attractive benefits that their citizens would like. Not to impose sanctions or criticise or add to their burden, but assist them in improving the lot of their citizens.
Using military power + soft power against lesser developed states, or economic power + soft power against them, without providing support and aid and trade and opportunities just creates more problems. Using soft power can hurt both sides; it is then just another form of international warfare. I wonder if this is what is sometimes meant by ‘cultural imperialism’?