It was completely taken because it sounds cool.
Praetor really just means elite person or premiere man in Latin. It was a magistrate position. We just think of the Praetorian Guard, who were literally just “The guards of the premiere men.” They May have been good soldiers. They may have been a more honorary position for men of a certain class who never even finished soldier training. The position tended to flip between pretty much ceremonial to honoring the best depending on the time period.
You could maybe make a case for the robots to be some vanguard force. So they are premiere. But that’s not the kind of premiere that “prae” implies anyway. Or maybe they’re the best robots?
In any case. They should have picked a better word.
I wanted my Roman Graves holding a fucking Balista.