"synthesize bacon from basic protein building blocks."

They enjoy killing and eating real humans.

 "ANIMALS EAT OTHER ANIMALS"
'While it is of course true that animals do eat other animals all the time in nature, basing our own ethics, as humans, on the actions of animals, can lead us to all sorts of problems. If we can justify something solely on the basis that animals do it, then we can justify the following: urinating in people's front gardens (dogs do it); sexually penetrating females without their consent (lions do it); smothering our babies to death (lions also do it); vomiting on people's food (flies do it); and so on. People only seem to be interested in justifying human behaviour on one thing that animals do, and that's eating animals.'

https://www.carnismdebunked.com/general-ethical#1