I agree this was a really well-done episode. I did feel it was a little twee/sweet that they portrayed the mother eventually deciding not to have her daughter cut, but her speech was powerful and I agree it was better to show the complexity of it rather than some nice middle-class voiceover.
There's a brilliant book (and a series more) by a woman called Waris Dirie, who describes how she actually asked her mother to have her cut when she was growing up, because she associated it with being an adult. 
So terrible.
Cliterodectomy was practised until very recently in the UK and the US. I read about a woman who was treated for masturbation when she was a very young child. She was operated on under anaesthetic, and when she woke up she says she remembers just gradually discovering it didn't feel nice any more to touch herself, so she stopped. But of course much later on she discovered what had been done to her. If I remember rightly, that was in the 1930s or 40s.
Going back much further, there are lots of medical writings in the European tradition about it. There was a school of thought that unusually large clitorises gave women excessive sexual desire, or misdirected their sexual desires towards other women, so cliterodectomy was the 'cure' for lesbianism or promiscuity.