What do you think the purpose of Colonialism was?

"Colonialism" does not exist as such. It's merely a sometimes useful intellectual abstraction, not a real thing. It has no objectives or purpose, because it does not and never actually existed as a real thing. It's merely a summary shorthand for a certain set of ideas.

Trying to impute motives to an unreal analytic abstraction is the reification fallacy.[1]

[1] https://en.wikipedia.org/wiki/Reification_(fallacy)

> "Colonialism" does not exist as such.

That is an empty refutation...

Colonialism was(is?) as very real practice. I really don't understand how you can claim that it is an "intellectual abstraction"

You went to Wikipeda for the definition of reification, but not for the definition of Colonialism[1]?

[1] https://en.wikipedia.org/wiki/Colonialism