A society that consists of strong and powerful members is stronger than one with selected elements oppressed. For every weak member a society is that much weaker. It is anyone’s best interest to encourage everyone around them to be as powerful as possible. Fear of loosing one’s privileged position, and resentment towards those even slightly different than oneself are key destructive attitudes keeping societies weak.
Because the world economy is highly interconnected actions anywhere on the planet have global consequences. If China’s economy is weakened because of an embargo, it harms every country’s economy; if Iran’s R&D sector is withheld information and held back, it hurts technological progress all over the world.
This principle applies on a much smaller scale as well, when elements of a society are kept weak, it weakens the society as a whole. In a number of muslim majority countries, women, nonmusilims, and men without suitably bushy beards are prevented from learning valuable education, or otherwise from engaging in anything that matters. A rich prince of Saudi Arabia may find this quite comforting, as he is surrounded by wealth and comfort–but even from a purely selfish perspective, and even for those at the top, this system is highly destructive and seriously hampers economic and technical progress for that country.
You shouldn’t strengthen others for altruistic reasons or out of a desire to do what is right, but rather, because it is the only sustainable way to promote progress and stability. Whether you care if someone is happy or not isn’t relevant. They should be strengthened for the purpose of strengthening the entire human race, and ensuring forward progress. Even if a force has certain destructive tendencies, one must weigh the forces contributions with its detriments, and whether or not it is heading up or down.