The right number is the one which nature will support, and sadly, that probably means we'll push out the wildlife entirely. My point was that there is a contradiction between a) our stated desire to protect remaining wildlife, and b) our failure to master our own instincts.

Our strongest instinct is survival, closely followed by resource appropriation. Both are the enemy of wildlife, yet we love wildlife. To remove the contradiction we'd have to dominate our survival instinct and reduce our own population, with all the awful moral and ethical consequences (for humans) that that would entail.