Having a hereditary monarchy in this day and age seems ridiculous. Having an official state church is equally ridiculous. When both anachronisms are simultaneously present, they give birth to the kind of absurd controversy currently taking place in the UK.
What’s the problem? The current government wants to change the law so that the British throne does not pass preferentially down the male line as it does at present. This move seems to have general support. But as part of the package containing that reform, the government also wants to eliminate the prohibition passed in 1701 against the monarch marrying a Roman Catholic. (Yes, that actually is against the law in the UK!)
Apparently Prince Charles and a former Archbishop of Canterbury are against this latter change, outlining a possible scenario in which the monarch marries a Catholic who raises their child in that religion and that person then inherits the throne. Why would this be a problem? Because the monarch also serves as the titular head of the Anglican church in the role of Supreme Governor of the established Church of England. And having a Catholic as the head of the Anglican Church would undo all the work of Henry VIII and his successors in attacking Catholics, wasting all those beheadings.
Here’s a simple solution: Eliminate both the monarchy and the established church.