And who fancies a little friendly bet as to the outcome of this case had the "prayer giver" felt like addressing a somewhat less popular deity?
I'm actually pleased that they didn't go with the "well, don't blow the dog whistle too hard; but, because reasons, any suitably vague approximately protestant invocation is just good honest tradition, and thus not a problem!" nonsense that is usually implied by 'non-sectarian prayer'; but the disconcerting bit is that they don't appear to have addressed who gets to pick the religion that will be imposed on everybody's patience today. That seems like the crux of the issue.
Yes, pretending that you can 'non-sectarian' a religious exercise to the point of safety is nonsense, and imposing that just means you'll get your majoritarianism with a few of the more galling buzzwords stripped.
However, so long as you have a state entity imposing the religious practice most pleasing to the majority on everybody, you've got an establishment problem.