I don't really get why you are all so scared of them - there's only a dozen of them and they look to be in poor physical shape. They don't seem to have any identifiable superpowers.
If you all just ignore them as you would other crazy old dudes in institutions, what are they going to do? Kavanagh might get drunk and blub a bit, which would be embarrassing for everyone to witness, but I struggle to imagine the dozen members of the Injustice League being able to physically do much to enforce their rulings (though, now I think of it, maybe that _could_ make for a fun MCU movie).