I don't like categorical imperatives, but if I had to design one I would basically say any adult should be able to freely marry any other adult. That said, I think nearly everyone experiences some expectations from their relatives about who they marry and they are
"obviously sectarian/classist/racist/et al. in practice that our culture looks past all the time so I don't know why someone would claim to be shocked "
That said, there are obvious differences is again in degree and context. The judge was particularly ham fisted in his bigotry (which is especially galling considering his role as an impartial justice). It is worse to disown your child than to refuse to attend or financially punish them than to simply encourage. The underlying reasons also matter, invoking the Holocaust, the Armenian genocide, or Amish ideas about living apart plays better than standard white supremacy.
I don't feel the need to condemn everyone on this, but do you think it is a fair comparison between an Indian family refusing to pay for a wedding with a match chosen by their son and this guy? An Amish disowning their son that leaves the community vs. a white evangelical family disowning their gay son?
I think context matters a lot even for stuff I would condemn for within my own family or social group.