Africa could never have risen on a population of 300+ million as it was in the 1970s. Anyone who would of said otherwise was either misleading or ignorant. And nothing has been derailed if your main goal was population growth!

"But a number of African leaders, including Uganda's president, Yoweri Museveni, believe that their countries are underpopulated, and that a bigger workforce will boost their economic prospects. In a speech to MPs in July, Mr Museveni said: "I am not one of those worried about the 'population explosion'. This is a great resource."

https://www.irishtimes.com/news/uganda-s-population-growth-set-to-match-that-of-china-1.1042592

As for the crime rate being cut down, if I was a betting man I would give you 100 to 1 odds that the crime rate will be cut down, at least within major urban areas. I say this for the simple fact that with new sensing technology, cameras, autonomous drones, and a few other emerging tech, it would be almost impossible for a person to commit a crime and get away with it. And we are not talking about tech that is 10 to 20 years in the future. We are talking about tech that has already been developed and is either being perfected or rolled out.