Malaria is more akin to an exploit than a vulnerability.
However, if we are to persist with your example, what you are trying to say is more akin to "Studying malaria and developing, or buying, a genetically engineered infectious disease that uses malaria's infection vector, and stockpiling it in a warehouse, and sometimes secretly using it, and not telling anyone about this isn't making people any sicker."
Even if they wouldn't "hop into bed" with other governments, if they had hopped into bed with the US govt. they would have lost revenue in those other markets, which would be likely to view Apple products as backdoored by the US government.
As a multinational company, it's in Apple's interests to maintain a 'no backdoors' strong privacy stance, or it will both lose foreign markets (that are afraid of US/other nation's backdoors) and have to contend with increased requests from various governments for backdoors/audits (they got backdoor access, why can't we?), and the associated revenue lose.
