I'll repeat what I said upthread: if in the story, it's shown as wrong, then I'm not going to care a lot about how they choose to call it. I think it's cowardly, but the first thing is to think that it's wrong.
Except that plenty of people read the story and saw it as NOT showing that this act of rape was wrong, and as it turns out, we were half-right, because the author herself insists that it's not rape at all. You've argued that Grayson's critics have read her intent incorrectly, and you're already half-wrong on that score, by Grayson's own admission, but even if I was to be charitable and believe that she wasn't glamorizing this instance of "nonconsensual sex," the fact that so many readers saw it that way, even before they read what Grayson had to say about it, shows how badly she failed in her attempts. At best, she's incompetent, and at worst, she's secretly sympathetic toward Toarantula.