I imagine that a Robotic Empire wants to turn into Synths as a Hive Mind wants to embrace Individualism.
Robotic and Synthetic Empires really aren't the same thing. The first ones are a Hive Mind controlled by a computer and view the world as an emotionless computer would, the second are individuals in robotic bodies who view the world like biologicals do. It is confirmed that they generally like one another in 1.8, but when you look at it rationally they should be terrified that the other would try to corrupt their software (and frankly, they probably would want to convert them).