Not talking about civil — the issue is whether or not the marriages this rabbi performed were halachic. Jews are answerable to a higher authority, and much more involved. These interfaith couples were married under the false assumption their marriage was sanctioned by Gd and of course it wasn’t.
Also, no Conservative or Orthodox rabbi perform same gender marriages.
I had a roommate (the 1960s) whose brother was a rabbi in a liberal synagogue. He would eat bacon and give his kids bacon but tell his small children it was pastrami so as not to have the kids open their mouths in the wrong company.