She sees loneliness as a unique disease. Malady means disease. The other question you might ask is does she see it as curable at some point? The answer to that is very difficult and yet very simple.
Most authors when they write about social qualities around them, see the world (or the part they live in) gripped in and strangled by the problem they are writing about.
McCullers wrote the Heart is a Lonely Hunter in 1940 just before America's entry into WWII. America had just come out of a depression, the worst on record since America became a nation. There is good reason to believe that loneliness and isolation of people was a serious problem.
That feeling, up until Pearl Harbor, was reflected in America's Foreign Policy. Most people did not want to become involved. The term used was isolation.
There are open studies on the internet that show that marriages were in a decline for WWI to WWII and then spiked in the 1950 to the highest level in American history since these stats were tracked. I am recording this to show that McCullers thought that the hardships of life sometimes mold our attitudes towards others.
