The Justice League is Making Horrible Recruitment Decisions
Look the Justice League has seen some real hard times lately. Batman, Superman, Wonder Woman and J'onn J'onnz are all not currently on the team in the DC Comics Universe. So the League is desperate for some real superheroes, because right now they're relying on Vixen to save the world.
Yet as you can see above they turned away Super Grover for membership, who is not only one of the greatest superheroes to ever grace our planet, but has an amazing handle on the alphabet. So the Justice League chose Super Grover over Aquaman. Well, I guess the letter of the day must be M - for morons.