Bribery and aid being used for closer relations are not the same thing. A bribe is under the table, this on its own is serving China's interests. They don't need to be slipped some resource extraction money secretly for this to be a good deal for them. It is a country that just kicked out the French and US, is threatened by Nigeria, has a left oriented government, a ton of natural resources previously dominated by western firms, and is in need of allies and arms.

If China gave them all of these free of charge with no expectation that is still a huge bargain for China. Even thinking cynically it is stupid to treat this as a bribe. Burkina Faso needs this shit, China benefits from breaking western hegemony