Islamic school controversy: the news reporting is confusing me

After reading about allegations that a Muslim school had banned singing of the Australian national anthem because singing the anthem, or possibly the anthem itself, was against the "Islamic view and ethos", I'm now reading conflicting reports about what really happened. I'm confused about what was in the memo that's the source of the controversy. Later reports only heighten my confusion.

What exactly about the entire situation was against the "Islamic view and ethos"? The news reporting says that "his [the teacher's] proposal for students to sing Advance Australia Fair was ruled to be against the 'Islamic view and ethos'". It doesn't say what specifically about the proposal was problematic. But despite that my reading of the news report strongly implies that we should believe that there's something inherently incompatible between Islam and the national anthem as far as the school is concerned.

The school and its defenders are also disputing the characterisation of their actions as a blanket "ban". And I would dispute the characterisation of their actions as a ban as well, even if it turned out that the national anthem was never sung at any school event at all (which is not actually the case, as per the school officials): it's not as if the decision not to enforce the singing of the anthem is the same thing as explicitly preventing it. Calling this a "ban" makes no sense to me: something is not forbidden just because it's not actively promoted.

I'm also desperately trying to reach back in memory to my school years and failing: I don't recall if I was required to sing the national anthem at every assembly or not. I vaguely recall that I was expected to sing it at some, but I also vaguely remember some in which I didn't. My memory may be faulty or the situation may have changed, but is this school doing something unusual by not expecting the national anthem to be played at every assembly, if that's actually all that they're doing?

It's not entirely clear to me if the anthem was not going to be sung at every assembly or just some. The linked article in the Australian does provide the tantalising quote from the memo saying "the singing of the anthem will be put on hold", but provides no context as to when. Or why. I think that's the main problem I'm having here: the full text of the memo which is the entire source of the controversy is not being made available. By anyone - the newspapers quoting from it or the school that authored it. I find that disconcerting.

Where is the original text? Why is nobody making it available?