Humans and apes evolved in areas that were warm. There is no detriment to losing insulating fur in warm environments. Evolution does not take place because a species "wants" to do anything, it takes place because natural selection will pick adaptations that give reproductive advantages.
Given two sets of traits:
the ability to use tools, be relatively weaker physically, and be able to conceive and communicate complex ideas
or
being physically strong, but have no ability to use tools, no complex concepts/language
We can run to otherwise identical populations through the passage of time.
Given that intelligence and tool usage has allowed human beings to thrive in every climate on the planet, from deserts, to jungles, to plains, to forests, to arctic tundra, to mountains, to coasts, one could conclude that such a combination of traits quite easily provides a reproductive and survival advantage.
Losing fur and strength do not matter to tool users who can more than compensate for the lack of either. That is quite within evolutionary theory.