Is it?
While I freely admit that the notion of the monarch opposing the government policy is extreme. I can nevertheless easily imagine a number of scenarios where a monarch might intervene.
Some of the greatest threats to the democracy IMO don't come from outside, but from within.
These are three
current examples of proposed politics. I'll leave it to you to guess which countries I refer to. - That shouldn't be hard...
1) In a country where a political elite has taken complete power, distancing itself from their voters, who only have one serious alternative. That alternative is however unpalatable for many voters, because the party is either considered too extreme, too amateurish or the voters don't agree with the core values of that party.
The political elite has across the political divide decided to completely keep that party out of influence no matter what, even though it represents a large segment of the voters.
That's the background.
A bishop proposes to remove Christian symbols from churches, like crosses, and preferably turning them into multi-faith temples. In the holy name of political correctness the political elite decides to go ahead.
2) The nationalists have taken power in a country. These are people with a fondness for brown shirts and who tend to suffer from stiff right arms.
From the stance that this country is for the natives only, the government embarks on an "active" policy aimed on "persuading" people from certain other cultures and religions in particular to leave "voluntarily". - A new "kristallnacht" looming just around the corner.
3) At present your country is taking part in a bombing campaign in another country, against what are basically extremist barbarians who are in rebellion against the totalitarian government in that country. Your country would like to see that government toppled as well but that hasn't been possible.
Now, an old ally of that country intervenes militarily on behalf of the albeit totalitarian, but legal, government. That ally is a not inconsiderable military power.
A number of your politicians now advocate establishing no-fly zones over the country backed by force and if need be you shoot down planes from the intervening country. Other politicians advocate equipping rebellious fractions on the ground with advanced anti-aircraft weapons in order for them to shoot down planes from the intervening country.
The government in your country, smarting form having their pride hurt, agree. - Apparently ignoring the fact that such a course will lead to military confrontation, perhaps even war, with the intervening power. - Thus ending up defending the very same people you used to bomb.
- Finally may I remind everyone that the Nazis were democratically elected.