Food for thought: Do you think slavery is or was a “service to humanity”? Because that is what you are advocating: Forcing some set of people to work for free for another.

Also why do you think it has become so cheap in the first place?

This is not to say that eradicating malaria might not make a lot of sense by the way. But you are being incredibly disingenuous, and your argument is based on bad premises.