Welcome Wildsmurff, and coming on strong with an insightful first post! In a real life situation, then yes, they would be hounding Mon-El and Imra about how they handled this situation with Reign. That they didn't, is bad plotting coupled with a need to gloss over holes in favor of the direction the story is taking. They couldn't have those answers, and still have Supergirl losing that big fight. She lost because she had no intel on Reign and did not know her strengths, and she went in without backup. J'onn should have been there, as Mon-El should have been too. And Saturn Girl. That ability to underestimate her enemies, is one of Supergirl's bigger weaknesses.