But people are working to reduce the population by reducing fertility rates. I haven't met anyone who was openly working to reduce the population by increasing mortality rates or even by campaigning against efforts to decrease mortality rates.
It's possible that if mortality rates were reduced really dramatically, some population activists would get upset (and I've seen indications of that in other threads here).
People who advocate euthanasia and socialist health care programs are effectively increasing mortality rates. In countries where euthanasia is legalized, mentally ill people are already being killed.
When a bureaucrat sitting behind a desk can use a rubber-stamp to tell an elderly person, "Nope, no treatment for you this time, you're done," there's nothing to stop more and more people from being denied treatment. Eventually even younger people with mental illnesses or genetic disorders will be eliminated--all to avoid overcrowding and overloading of the health care system, of course.
It's for the greater good. Don't you want to be a good citizen? Reduce your burden on society, today!*
It's possible that if mortality rates were reduced really dramatically, some population activists would get upset (and I've seen indications of that in other threads here).