Depends on if you view killing them before they develop into what is considered a being with rights I guess. It's honestly the exact same debate as abortion. I agree with you, for what it's worth.
It's not the same as abortion at all. A droid can be given or sold to someone else who wants to let it grow into a sentient being. Fetal or placenta transplants simply doesn't exist. These two scenarios are simply not the same.
At the risk of introducing a contentious topic into polite discussion: there's an obvious parallel with abortion. It's seen as pragmatic, and maybe even kind, to terminate an entity's existence before it can achieve the intelligence and sentience that grant it moral rights.
If you're OK owning and operating a robotic arm, and not OK with owning and operating a sentient AI, then what to do with robotic arms that develop sentience over time?