Here is what some are saying.

Pros:
1. Colonialism Improved Health and Care System
2. Enhancement of Civilization
3. Restoration of Women’s Rights
4. Development of Infrastructure
5. Food Security
6. Political Development ( Democracy)
7. Reduced Poverty Gap
8. Literacy through Education
9.Democracy, Legitimacy, and Nationalism
10. Enhanced Defensive Networks (Imperialism, which came about during colonialism, enhanced defensive networks amongst nations.)
11. Attainment of Liberation ( Through colonization, people fought for independence to enjoy their liberty.)
12. Cultivation of Unity amongst Colonies

Cons of Colonialism
1. Colonialism Caused Constant Wars and Conflict
2. Loss of Culture and Identity
3. Extensive Loss of Land Amongst the Colonies ( Another downside is that they lost big acres of land, which were grabbed powerfully from them by the colonialists)
4. Heavy Taxation Imposition
5. The entry of New Illnesses
6. Economic Dependency Syndrome ( There was an increase in the economic dependency syndrome due to the colonial masters’ grabbing of the African resources. ).
7. Tainted Morality
8. Introduction of the Slave Trade
9. Initiation of the Divide and Rule Policy

More Details @ https://www.ablison.com/pros-and-cons-of-colonialism/