Why? its true there are too many of us. We keep fixing the things nature controlled our numbers with.
Dysentery, TB, polio, the flu, we have corralled most of it to the point of irrelevance to the greater population. To not think something else would be coming along is very short sighted. The planet, our very species exists because of genetic/biological switch ups.
Sometimes the dice don't go our way. Black death, Spanish flu etc.