The buck stops there.
If you have the ultimate control you have the ultimate responsibility.
Just what exactly do you mean by that? I will clarify my point. God is in control, however, He gave us free will, which means that we can do whatever we want. The problem is that He doesn't want us to do certain things, so He will punish us when we do those things. If we aren't aware of God's presence, we will make no connection between our actions and His punishment for them.
AIDS and other VD's are God's punishment for sexual immorality, IMO, the same way heart disease is punishment for gluttony and sloth (like LFD pointed out). So in a way, God is responsible for their AIDS because He allowed them to get it as punishment for their sins.
God is in control, whether you like it or not.