Well, yes, porn is tacky. And I agree that writing it about real people is even tackier and that's being polite! There were loopy fans doing it back in the days when B7 was a major fandom. The actors concerned were understandably upset and I wouldn't have blamed them for bring put off fans and fandom altogether, Nobody has the right to do that, Actually, writing stories about real people without their permission is yucky altogether, IMO. Some of my students do that - not porn, of course, they're way too young to have that imagination but I gather it's an accepted form of fanfic these days. But when I asked my young fan writers what universe they chose for their writing and they told me, I went, "Oh, yuck!" and asked how they would like to have it done to them.

No, I haven't heard of that novel you mention, but will look it up. She is a good writer.