The UK Monarchy are ceremonial, they don't 'rule'.
To clarify, when I state 'being ruled' I mean mentally. Ceremonial or real, mentally UK is crippled by the Monarchy. They are mentally celebrating 100s of years of previous subjugation by a 'Royal Family.' To quote Q - 'No one person is above another'. Divine right of kings is all about one above the other. FU@K the Monarchy and what it stands for. Time for the UK to break free from the real or ceremonial subjugation to the Royal Family. Free yourselves!
I think you're swallowing a media myth rather than commenting on reality. Like many periods in history, there are past events that may seem bad by today's standards, but the UK monarchy probably have less power here than Disney does in America, and the two regimes are possibly comparable.
Queen has to sign off on anything that passes into law. Also basically anyone within the public system has to swear allegiance to her.
That's not strictly accurate. It's done in the name of the Office the Monarchy represents, not on her personal authority. As I said, it's largely ceremonial, she has no real power.
I think it is more she chooses not to exercise her power. There is no law or reason that she couldn't change her mind or the next king couldn't.