I’d like to keep it short. Here is the main idea.
Most of the people in the world have caught a cold at some point of their lives. Most of them have survived. It is also the same thing for flu and for other diseases. While being sick is not fun in anyway, few see it as a life threatening issue. Few would wear full body space suit with its own oxygen for their whole life. Unfortunately, for full blown AIDS patients, that is not the case. To know how to avoid even the slightest disease can sometimes save their life, even though there is no way to restore their immune system.
Same analysis for governments. Check out the following story.