There is absolutely no proof, or even the tiniest niggling concept, of the origin of the HIV virus. In fact, the first AIDS case ever reported (not the British sailor - that was was a case of contamination) was in 1959, and there is strong evidence that it was endemic to the Bantu tribe for decades before that. This tribe lives in Africa, and has lived there for years. Long before rainforests began to be destroyed en masse, in fact, there were Bantus infected with AIDS. There is no convincing scientific evidence of pre-Bantu HIV.
What does this have to do with McDonald's? Of course, any huge corporation maintains some culpability when it comes to pollution and destruction of natural habitats, but the real concern is, unfortuantely, less practical and more emotional. Who wants to see the destruction of a species simply to create more farmland? I don't. But the idea that leveling rainforests is going to have huge negative impacts upon the human species (like introducing new pathenogenic organisms, reducing atmospheric oxygen content, etc.) is ludicrous. That still doesn't make losing the rainforests any less tragic, but the tragedy lies in the loss of diversity, and will probably ultimately NOT impact the human race.
P.S. The atomic bomb ultimately has saved FAR more lives than it has taken. Does this make it moral? No more than any other weapon, but the offshoots of the Manhattan Project have been very beneficial - i.e., nuclear power.
McSpotlight: Continuation of this thread would probably best be taken to the Anything Else room; it is drifting off-topic for the McDonald's room.