Elizabeth II was to the Angican Church as she was to the state of Great Britain, a symbolic head, unlike the British prime minister or the Archbishop of Cantebury. The former is the actual leader of Great Britain and the leter the actual head of the Anglican Church. The former has the role to speak for the positions of the government on matters of state, and the later has the role of speaking for the Anglican church on ecciesiastic or theological matters; not the Queen/Monarch.
You expected from the Queen what was not in her official duties to do.
Nonsense. Every Christian as an ambassador of Christ has an obligation to speak the truth using the platform God has given. Official duties is a cop-out. What ambassador in any realm fails to deliver the foundational message from whom he is sent? It doesn’t happen.
I have no “official duty” given by man, yet I use whatever platform I have to tell the truth, chiefly to warn others out of genuine concern for them.