They never had a chance to search for the origin. They were trying to restore the star and return their loves ones. Maybe give them a minute to process having narrowly survived an extinction level event before deciding that they're hopeless and need to be sundered. Better yet, tell them what it is they need to do to adapt and overcome. Venat's message wasn't successful because it was a bad message. No one in the midst of trauma and grief wants to hear that they should just accept their suffering and move on, it's callous. Not to mention that would not have helped them confront and defeat Meteion anyway, in fact, the Omega quest chain basically debunks Venat's entire thought process in that regard.