I was fascinated by this Strange Horizons piece
and the ensuing Twitter kerfuffle. I'd go over and read the piece, but to summarize crudely, Renay is arguing that creators ought to stay out of fan discussions of their works. Her argument is something like that creators are invading fannish spaces and imposing their canonical authority in places where their input isn't welcome or productive.
Some scattered thoughts in lieu of a coherent response:
1) Whenever I post anything online, I do so under the assumption that it's going to be read by my mom, the police, and the people I'm writing about. Does this mean I would feel totally sanguine if the creator of a work I'd reviewed negatively came in to comment on one of my reviews? No, because I'm somewhat conflict averse and I don't like making people feel bad. But if I'm not willing to run the risk of that happening, I don't post online.
2) In the SF book fandom that I grew up in, the line between pro and fan has always been extremely porous. Even before the internet, you always ran the risk that an author would see your negative review in a fanzine, or that they'd be in the audience when you said something about their work on a convention panel, or that they'd overhear you talking about their work in the consuite. Sure, fanfic was something you didn't wave in authors' faces, because of the legal issues and because it makes some writers uncomfortable. But, in general, the mingling of fans and pros has always been a feature of the fannish spaces that were most important to me. Clearly Renay's experience of fandom is very different.
3) Okay, let's talk about authorial intent. Yes, it's true that as an author, you have no control over what readers take away from your work. Ultimately, what the writer intended has no more validity than any other well-considered interpretation. However, it also doesn't have less validity. As a reader, I'm interested in what the writer was trying to do, even if all I can do with that information is say, "Wow, you sure didn't achieve that."
4) Are authors asserting power when they step into a fannish discussion of their work? I don't see it that way - the fannish culture that I talk about in point 2 above has always been pretty egalitarian about the relation between pros and fans. I have run into some authors here who don't get the fallacy of authorial intent and go around being dickheads about alternative interpretations of their work, but that's just people being dickheads.
5) I do think there is another dimension of this: in at least two of the examples Renay cites in that essay, a creator waded into a discussion in which issues of sexism or racism in their work were being discussed. And in a context where the creator is white and male, this can end up looking a lot like a privileged dude mansplaining away the unsavory aspects of his work. I looked at the discussion of Ben Aaronovitch's Peter Grant novels linked in Renay's essay, and I genuinely don't think that that was what was going on there. However, I can see how people might perceive it that way, and I think, ultimately, it's probably more important for people to be mindful of that dynamic than of the pro/fan dynamic.