This question is incredibly complex. It is certainly true that Africa would be a much different place if Europe had not colonized the continent. I'm inclined to believe it would be a better place but there is really no way of knowing. I think historians can only say that European colonialism in the 1800's played a major role in shaping African history. Philosophers, politicians and activists are much better suited to assigning "blame".

While you wait for a proper answer check out the FAQ - Why is Africa "less developed" For some good perspectives on how colonialism affected Africa's development.

This is a reallllly dangerous and imprecise question to ask. For one "blame" is not something used lightly by historians, anthropologists, sociologists etc. I think that your question is predicated on a biased/modernist view and you may need to narrow it down quite a bit. For example, if you believe Christianity is a negative or positive influence on the modern world, a similar question would be "Can Constantine be blamed for the Bible Belt in America?" or "Can Muhammad be blamed for ISIS?". When connecting the past and the future, you have to look at it through both lenses, ad the perspectives of everyone in between.

Looking at your responses to other answers in this thread, it seems as though you (intentionally or not) see the current conditions of the entire continent (second biggest and second most populated and most diverse btw) as primarily their fault, with some crucial influence placed on imperialism. As though what happened during the imperial period was just a push in a certain direction.

I'm not going to answer your question because it seems set up for failure, but I'm trying to give you lessons on critical thinking and asking the right questions. Asking the right question is as important as giving the right answer. Read through a couple other top posts in this sub, particularly non-Euro-centric questions. An easy one is reading about the Ottomans, which is a very hot topic because of the 100th anniversary of the Armenian genocide. Get some examples for meaningful questions and come back in a bit. This is not to dissuade you, I understand what you're trying to learn, but you'll end up a lot better knowing how to ask the right questions on such broad topics.

EDIT: I forgot the most important thing to think about and that's "Would it have been so without ____?" A good example of this is the Mongol conquest of Russia. The Golden Horde (the European subsection of the Mongol Empire) included Ukraine, Hungary, Russia etc. It was the first time that the various polities of Russia had been unified. From a modern perspective this seems extremely important, especially considering the importance of Russia from Napoleon to Hitler to the Cold War to the Putin situation (~200 years). But without the Mongol conquest, would Russia have ever undergone unification on its own? The answer is we don't know. No amount of theorizing and speculation will answer that question. It may increase the probability of certain outcomes and influences but we can never know. Same for this question. We will never know if the Kongolese kingdom or the Ashanti or Zulu etc would have flourished naturally into "developed"(again, think about what developed means from a non-modern perspective) countries or if they would have become corrupt lands anyways.

A good written source that would cover quite a bit of this would be Fred Cooper's Africa Since 1940.

He lays out the idea of the gatekeeper state, which, to put it simply, outlines why the colonial governmental structures in Africa were set up as exploitative ventures, both in terms of resources and human capital. With the sudden rush of decolonization in the 1950s and 1960s, states became self-governing, but the the methods of government remained exploitative, thus leading to the extreme corruption issues.

I highly recommend the book, both for this theory and its general overview of the end of colonial Africa and the different ways that came about.

Edit: Whoops! Mis-typed the book title and wrote "research" instead of "resources"

Although I'm not a historian I think I can provide some interesting insight from an economics perspective. I would read two works by an MIT economist Daron Acemoglu, one is his book "Why Nations Fail" and the other is his excellent paper "The Colonial Origins of Comparative Development". Acemoglu makes the argument in both works that the success of modern day economies is largely drawn from quality institutions.

In the colonial origins paper, which hopefully is appropriate for this sub, Acemoglu argues that one of drivers behind quality institutions today is the mortality rates of the settlers. Acemoglu argues that the determinants of whether Europeans could go and settle in the colonies have a very important effect today on the quality of the institutions in a country. Because these differences are a source of plausibly exogenous variation Acemoglu is able to estimate the impact of institutions on present day economic performance. He finds that areas with lower settler mortality rates, like the United States or Australia, quality institutions were set up that mirrored the country's that the settlers came from. These institutions that were implemented protected property rights, established a working judicial systems, and encouraged investment. Other areas, like the Congo for example, had extremely high settler mortality rates, which discouraged many potential colonists from settling. As a result the institutions that were set up were designed to be extractive and to reap as much profit as they possibly could. The colonial legacies have left a lasting impact on the current day institutions, but it is important to note that they aren't sole determinant of the success or failure of a country's economy. This is of course only one relatively narrow view on the matter, but it is nevertheless a interesting and important perspective.

Hopefully that is somewhat coherent, this is my first time posting on this sub and I'm an economist by trade.

No joke my History 103 class at CWU is writing a paper on this due tomorrow.... I really hope that's a coincidence