Indeed it does take two or more. I think those that wish to make this an "issue" want us all to overlook, ignore or just be plain ignorant of the fact that the Royal Family represents the UK. Every foreign head of state that meets the Queen and enjoys a royal state banquet does so at the invitation of the government. And, you had better believe that the BRF representatives are as politically well briefed on the stance of the government on any pertinent subjects as are it's political representatives.
The Queen has "fronted" for the government officially for 60 years as indeed has her husband. The Prince of Wales, the Princess Royal, Princes Andrew and Edward and their families have all been ambassadors for their country. The notion of them being politically naive or ignorant is more than a little counter-intuitive.
Foreign dignitaries do not just chat over their pre-dinner sherries when at Buckingham Palace or Windsor Castle. They talk about the world and their place in it. Members of the government also involve the Royal Family in so very many different ways. The most glaringly obvious is the Opening of Parliament. HM may read the speech but it's content is dictated by the government. But the Queen has never been a bubble head who just "reads" what she is told to, she has always striven to understand the message which, considering some policies, is no easy feat.
Just like the President of a major corporation, HM needs to know what she is talking about. And, when it comes to the Commonwealth, well let's just equate HM's role as had of a very large Multi-National Corporation.
It is all politics and fumbling and stumbling around in ignorance ill befits the BRF and it's role in a Constitutional Monarchy. In short, the PM doesn't visit the Queen just for the tea! In such a world it would be impossible for Charles to be "ignorant" of all until the magical moment of Coronation whereupon he would be expected to know all. Think of how many years ago he was created Prince of Wales and then think of that as "an entry level position"!