The Nazi’s gave up on mobile execution vans using truck exhaust, because the victim would often first suffocate, in the process their was vomiting and deficating. Cleaning the vans took a toll on morale.
Conversely, a Planned Parenthood staffer sorts through a dish with a freshly torn apart baby and says...with a modicum of joy: “Oh, it’s another boy!”
Also the experience at Babi Yar convinced the higher-ups there had to be a better way. Especially since they had to go into the pits and shoot those who survived the volley.
Which is why they forced the Jews in the Sonderkommando unit at Auschwitz to clean the chambers for them.
In contrast, PP keeps it all in house and in the family. A bunch of truly sick, morally diseased human beings.