This was the high court in the UK, so what does that have to do with American history, and history of schools, not individual homes?
They are not just talking foster kids, they are talking adoption. If a Muslin adopts a child, they rear that child as a Muslin, If a Native American adopts a child, they raise him/her in the Native American religion. If a Hindu or Buddhist adopts a child they raise them accordingly.
But even with foster children, you include them in your family activities. You aren't going to single them out and exclude them and you aren't going to give up your beliefs to raise a foster child. All religions, except for Christianity, and share their faith. Just like in the schools of California now, where Muslins can do things & observances of their faith in school, teachers can share/indoctrinate with anything and any religion EXCEPT anything Christian.