Latter Day ZPG?

The liberals, who in the 1970's began championing zero population growth (ZPG) are now hell-bent on tearing down our borders, with some estimates running as high as 100 million new immigrants in the next 15-20 years. And the ZPG folks were wildly successful, having reached a low of less than replacement level.

Need anyone ask why these folks, with their ZPG, eco-freaking, and open borders have earned from me the name lemmings?