It's a very interesting topic. Without going too much into philosophy or existential theory, I'd like to refer to the '
teleporter conundrum'.
Essentially, imagine a situation in which a self-aware entity is destroyed on an atomic level - but simultaneously, a completely different set of atoms are assembled into a perfect, functionally identical copy of the destroyed entity. Are the destroyed entity and the created entity the same person, or two different people? Is there an 'essence' of consciousness that is transferred between the old and the new, even if no material is transferred on an atomic level?
More importantly, what happens in that scenario if, for instance, the teleporter does not successfully disassemble the 'original' self-aware entity, yet still manages to create a 'new' person at the receiving end using data that was sent to it? Does the 'original' need to be destroyed to preserve the authenticity of the 'new' person? Would the 'new' person be destroyed to preserve the authenticity of the 'original' person? Would the person fight back, realizing that their consciousness is essentially being taken out of existence?
There are perfectly rational, solid arguments to made for both sides (notwithstanding that the entire scenario is impossible with our technology at present) - either that A) The newly-created entity is a entirely different being from the original entity, despite identical appearance, and that the 'original' entity is now irreversibly dead, or that B) The 'original' and the 'new' entity are simply the same person for all intents and purposes - carrying the same memories, capabilities and capacities.
The Fallen Empire Materialists probably fall into the former train of thought in how they view Synthetics - while they probably do not care for a Spiritualist explanation of the soul or the conscious, I imagine they perceive "Synthetic Ascension" as a heavily misinformed act of mass-suicide, caused by a high level of technical knowledge combined with an utter lack of rational introspection. I imagine they'd be all the more disappointed at such a display, rather than envious.
"Aha! The robots can't kill me and replace me with a lifelike robot, if I destructively scan my brain to replace myself with a lifelike robot first!"