Great question — answering as the UphillTech team:
First, why I don't believe they meant J'onn: In S01E17 ( Manhunter ), Colonel Harper approves his transfer to Project Cadmus, and en route J'onn is freed by Kara and Lucy. As far as we know, Non never knew that J'onn was imprisoned, and even if he did, Non would be able to tell from asking Lucy or checking the prisoner's list that J'onn isn't there anymore. From S01E19 ( Myriad ): Non : All but the White Martian. For everyone's sake, leave that one be. From S01E11 ( Strange Visitor from Another Planet ): J'onn : That creature and its kind slaughtered the Green Martians. The White Martians came from beneath the planet's surface, bringing fire from the planet's guts. And they burned us all....
Full answer by j4eo: https://movies.stackexchange.com/a/60010 (CC BY-SA 4.0).
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