As for the disease, the disease is that atheist philosophers suffer from a type of mental dyslexia.
People with dyslexia cannot focus on words, and thus have difficulty with reading. The letters jumble too much in their minds as they read, so they cannot distinguish between "unite" and "untie," for instance. With many people, it is the same but for ideas. They cannot focus on an idea and apply definitions and previous theorems that they learned earlier. This is why half of programming students are incapable of learning programming, because that same ability to focus on concepts without them jumbling is what is necessary to do good programming, as it is for non-solipsistic philosophy.
Take essence theory versus bundle theory. The contemporary notion is that "essences" are just ad-hoc nonsense while bundle theory is more "erudite" and "scientific." So defining God as the being whose essence is his existence is nonsense. But why are essences so stupid? According to the moderns, because we use the attributes of objects to distinguish object from object, while we cannot do the same for essences. But we also know that there are some things that are incidental to an object (hair color) while there are others that are not so incidental (capacity for reason), so if usage is the determining factor, why don't we acknowledge that our usage of nouns/things reflects essence/accident distinction? Because essences are "spooky." But how are essences more "spooky" than properties? Because we use properties in our day-to-day lives. Ah, but you see, the dyslexia has manifested itself now: essences are also used in daily lives, but the person arguing could not recall the definition of essence ("that which is not incidental to an object") during the discussion and consequently resorted to something (perhaps a mental image or picture thinking).
It is my personal belief that the root of all atheism stems from this kind of mental dyslexia. All atheist thinking is possible because they cannot focus very well on one idea at a time, and when they do, they cannot pull definitions and theorems as necessary.