I don't tend to read real-person fanfics, but I am constantly reading fanfics of my various OTP's from my shows (Especially Torchwood and The X-Files). I won't lie though, I have read a couple in the past for my old fandom, approximately 5 years ago. Most of them were actually pretty well-written. I personally think that as long as it is respectful to the celebrities and their families and personal lives, there isn't really any harm in it. I personally only will write about fictional characters because I'm not really comfortable with writing about real people.
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"Have you never seen something so mad, so extraordinary... That just for one second, you think that there might be more out there?" -Gwen Cooper, Torchwood