At the end of the day, hearing the LGBTQ groups is unlikely to have much impact on the decision so why not hear them so as not to issue a verdict that some will say would be unjust otherwise..  Some of the groups that were originally granted intervenor status have as solid a grasp on the legal issues as one could expect since they were working with LGBTQ groups from the beginning.   Can the LGBTQ groups present better legal arguments?  Maybe but I doubt it.   More likely, they will hurt themselves if they attempt to make this case about themselves to the exclusion of everyone else.