I'm sorry but how can you possibly not have Defender leveled up by now? Sure you don't need it, but most teams just want to get in and go through the raid as smoothly as possible. For that, the more Defenders the better. If someone is putting together a team, it's their decision on who they want in their. Nothing you can do about it. Make your own team of strikers and sunbreakers if it bothers you so much.