Fascinating. The article quotes the attorney representing the school
“The question before the court was whether or not private religious schools were subject to state anti-discrimination laws,” he explains. “[Essentially] does it violate those laws for a private religious school to say we want our students to abide by our beliefs and to live according to rules of conduct that are consistent with those Christian beliefs?”
If I understand the case correctly, the students were not expelled for being intentionally disruptive in proclaiming their activities, but for participating in such activities at all, even though outside of school.
This might not be an issue in say, Mississippi, but of course California has sexual orientation as a protected class, alongside race, color, religion, ethnicity, etc. Constitutionally, a similar question is whether a school could eject students for attending Catholic mass.
I’m not sure whether private schools have the same leeway that private organizations have to ignore discrimination law, since the Dale decision in 2000. I’d guess probably not - I’m skeptical that a school could exclude students on the basis of race. But schools do have considerable authority to regulate student behavior, even that outside of school and only indirectly related to the school. Whether the lesbian activity qualifies, and whether the fact of it being lesbian can be treated differently if other students have not been expelled for similar “straight” activity, are questions that I don’t think are clear yet.