Large amounts of money to hire and/or train rangers ,vets and support staff come from hunting. The countries involved also make tons of cash from permits and fees for hunts and transporting meat and trophies (majority of meat is usually donated to locals.
A managed population of animals is actually much healthier when older or unhealthy animals are culled or tagged for these kind of restricted hunts .
Almost all of these tags cost 5-50,000+ us just for the animal . . thousands more to local economies for guides,transportation ,hotels etc.