The earlier poster has a name. Fight me you coward!
We don;t need fewer westerners. They is less of us anyway. Which is the problem with the population size argument. It ignores other, arguably more important factors. Like energy consumption. This is basically a class issue where the even the lower classes of the west enjoy enjoy the status of a "labour aristocracy" as lenin put it. The higher classes of earth are smaller in number but consume much much more of everything, often relying on the high in number labour of the global south. Just focusing on population size makes it look like the global poor are the problem and not the global rich. It is reactionary dangerouse garbage and totally fits into an analysis that demands Nazi like solutions.
It is always conveniant that those who must reduce thier population size are the blacks and not the whites with thier low low populations but masive energy and resource consumption.
The human population exploded a long long long time ago. Well before recorded history. We have been destroying biodiversity for eons. We are already to far gone and there is no going back to noble savage style of existance. And even then our noble savage ancestors wiped out all the megafauna they encounted. The only hope we have (that doesn't involve killing that makes the holocaust look like childs play) is to find ways of making our mega consumption of energy and resources and viable in the long term. We cannot go back to being even subsistance famers, never mind hunter gathers with the amound of poeple who exist now.
I'm not even convinced the eradication of life on earth is holey a bad thing to be honest. We may find biodiversity asthetically pleasing when we watch out natural blood sports on TV. Nothing more beutiful than watching an antelope get eaten alive by a pack of lions. Large scale biology is cruel. Which is the only place you can even begin to say that existance might be a good thing. Biodiversity and complex ecologies are so dependent on r-selection creatures. K-selection is much better for the individual animals, but it is much rarer. Once you get into that sphere of life it gets even worse. Don't even get me started on the lot of insects. Biodiversity? Good ridance I say.
Honestly if we killed most of none human wild-life on earth but found a way of still propogating our species. Eg we live on mars on green energy, grow our food in test tubes and labs. That would probably be morally preferable to be honest. Myabe we could take the oragutans and dolphins with us. Or we just go extinct like the vast majority of life that has ever existed on this planet.
We should absolutly go down fighting, but we may just have to accept that we are an extinction event.