The main conflicts that arose from both sides was arrogance, competition, and miscommunication. First, the Louis Pasteur Institute in France was studying African natives or people who were in contact with the African continent and noticed that the symptoms expressed by American AIDS patients were similar to the symptoms they were dealing with. However, it was hard at that time to make an instant connection considering that it was mostly the gay American community who was getting sick at first.
Both sides agreed that a virus needs to be isolated to track down the causes of this syndrome. The problem began with trying to first find funding (who would get funding first to proceed with further studies), second, whoever gets the funding would have leading rights to name himself the person who ultimately discovered the virus which causes AIDS. Then, it is the doctors' interest in finding a vaccine. After that, whoever will get the credit for finding the cure of AIDS would literally be at a Nobel Prize level, so the competition was fierce.
Therefore, it was a combination of wanting to help and wanting to win what basically drove the investigation.