This behaviour is explained on this Meta.SE question:
If you vote to close your own question as a duplicate of something else... and refresh the page, you'll see the "your question may already have an answer here" banner. Clicking the "that solved my problem!" button on that banner results in Community instantly closing your question as ...
There was a comment by the initial close-voter; I can't remember it exactly, but it was to the effect of:
The UK and US are similar enough politically that the answer will be the same.
Unfortunately, they edited that comment into the auto-generated "Does this answer your question?" comment, which gets deleted once the question is closed, so you must not ...
There is not a consensus in the Stack Exchange community about exactly where to draw the line on duplicate questions. Some people favor a strict definition:
A question is a duplicate only if it is exactly the same question as an existing one.
Others favor a broader definition:
A question is a duplicate of another question if the answers on the duplicate ...
It appears that the author's intention was to create a dupe-target for general questions about the powers of the British monarch.
This is a good intention. When there are question which sound slightly different but always receive the same answer, then creating a new question which covers them all, posting a good answer to it, and closing all the old ...
Regarding my VTD: your question consisted of two large quotes one from
'My son killed himself after circumcision' - BBC News (2019)
David Reimer - Wikipedia
And based on that you ask "Why hasn't the UK enacted a male version of Female Genital Mutilation Act 2003"?
Why would they enact an Act based on two cases, even if they are what you say ...