Because this is the punishment land, we got kicked out of the Garden. This non-Garden place has bad weather, parasites and allergens.
you basically summed up what the link I listed says- He makes the argument that it’s not localized judgments upon certain civilizations, but just a result of sin in general- Had we not sinned in the garden, there wouldn’t be these natural disasters-
Anyways the link is worth a read- but he says what you do and explains it in more detail=-