Thank you for directing me to that article. I actually have read that article previously, and my summation from this document is very different than this meme it seems. Might I caution against posting context-less web memes which incorrectly claim they are direct quotes from a historical figure?
As to your cited document, I see very little in this document which discusses the death of anyone or a lack of value of life. Indeed, she seems to advocate for educating people on responsible procreation and giving them the tools to follow their own best judgement to decrease, what she views, as a drain on the quality of life for the society as a whole.
Eugenics, in and of itself, isn't inherently evil. It is the methods and motives of humans which determine if it is good or evil, as Hitler has thoroughly demonstrated. Mrs. Sanger's methods and motives seem significantly less malicious that Hitler's from what I have seen so far. I am troubled by the potential implications of forced sterilization of the "unfit" but I would need to see more of her reasoning to make an informed decision on the ethical implications of her ideas.
I think I will have to read her book to try to get a better grasp of her ideology and stance on the issue of birth control and eugenics with fewer outside biases than the internet applies to the topics.