It would also be a bug to force people to associate closely with people they do not wish to, for whatever reason. A communal group differs from an open civic group in that people wish to live more intimately with each other than in other collectives. Its a privilege to be in the group not a right. It would also not be straightforward to determine whether particular rejections significantly involved conscious or unconscious prejudices. Not straightforward at all, yet the groups actions may be scrutinized, judged unlawful and prosecuted when appropriate by other authorities - but that is a different thing from confining it to remove the possibility of it acting unlawfully.