Basically, virtually everyone in the show - even Maureen Robinson, who has a background as an engineer - presumed that whether the robot was now "nice" or a threat, that it was a mere tool. The one exception was arguably Will, but in his case it's clearly shown to be an irrational bond formed in part as a surrogate to his dysfunctional relationship with his father. While as the viewer we are given a fair amount of on-screen evidence to suggest the robot is actually self-aware, no one on the show even posits this. So for example, near the end when the robot starts doing "Dr. Smith's" bidding, it's taken for granted it's because it's been "reprogrammed" by Smith, rather than it being pissed that Will - its friend - told it to commit suicide.
I dunno, when I see a robot in a science-fiction show, I at least expect the issue of self-awareness and personhood to be drawn into the discussion. But at no time when they were debating what to do with the robot did they consider the robot's potential agency as an independent being. It really stuck in my craw.