You certainly remember the Cuban Missile Crisis of the 1960s. Who supported Cuba at the time? The Soviet Union. Why did the Soviet Union support it? Because it was a neighbor of the American enemy, which, just months before the crisis, had succeeded in establishing nuclear missile launchers in Turkey, on the border with the Soviet Union. The Soviet Union supported the coup led by Fidel Castro and Che Guevara, placing thousands of missiles ready to launch on the island, just a few kilometers from the United States.
There is no free aid without direct interest. When I say aid, I don't mean humanitarian aid, as in wars and natural disasters, but rather economic and logistical support that strengthens the economy. Russia and the United States support their allies by providing various types of aid. The United States currently distributes military, financial, and logistical aid to all its allies around the world, to the point that this aid has become part of the general budget of some countries.
The example you gave shows the difference between a colonizer and an ally. The support of allies is solidarity. The foundations of unions are political, not economic. Whereas the colonialists pursue only economic goals. Moreover, it is possible to evaluate relations between countries on this basis. Therefore, it is not surprising that the colonialists lose their positions in Africa when the local population realizes that they have been exploited for several centuries in one form or another.