There have been several posts on this thread which allege that the transformation of Dr Who into a female character is a reflection of liberal or progressive politics. Frankly, I am puzzled as to how people came up with this idea.
As shown above, this is not the first time a ship's captain was similarly transformed. Further, super heroes have had numerous female enemies (Superman had the Spider Lady, Batman had Catwoman, and ultimately, Dr Who's enemy the Master changed into the Mistress). Back in the 1960s there was a comic book Superman episode where he was killed by Lex Luthor and Supergirl took charge of crime fighting.
Why was there not so much controversy when Thor was transformed into a female:
https://www.theguardian.com/books/2014/jul/15/thor-is-a-woman-in-new-marvel-comicbook-series
or Captain Marvel and others:
https://www.theguardian.com/books/2014/jul/15/thor-is-a-woman-in-new-marvel-comicbook-series
When I was browsing online for these links, I came across quite a number of other fictional characters who made similar transformation. Historically, several mythical gods/goddesses changed gender identity such as the West African god Shango'. Gender based changes for heroes and villains is as old as humanity. There is no indication or historical evidence that politics had anything to do with these changes. While everyone is free to view the current change of Dr Who as such, they should give some evidence to prove their claim that the change was made because of political motivation.