Population is but one aspect of over-consumption. There are regions however, for example Egypt, or Saudi Arabia, where population size has clearly passed a sustainable limit already. Even without climate change there is simply not enough water to grow food for and thus feed this many people, not to mention the lack of soil nutrients - which has to be imported via man-made fertilizers.

The story of grain and fertilizer embargoes tells it all.

I don't know why and how population has become a holy a cow, but not discussing it clearly hinders any meaningful and peaceful action towards reducing our impact on the planet.

By the way, the country in which I live in Central Europe can also be counted among the overpopulated ones: currently we can produce enough food for ourselves in good years, but should water or fertilizer shortages get more severe due to drawdown of finite reserves (which they certainly will), we will be forced to import much of our food. From where - I do not know.