Yeah we didn't see what a lot of the other heroes were doing and that kind of to be expected . This show is the JL and they pretty much stay focused on those members (although a few cameos would have been nice). I imagine the other heroes weren't in the thick of things like the Justice League was and weren't privileged to a lot of the information that they had. The Justice League was seen as the main threat to the Thanagarians because they were the most powerful organized opposition they would face. a hero here and a hero there probably were a lot easier to take out.
"God has given me a gift. Only One. I am the most complete fighter in the world." - Boyka (Undisputed III)