Thanks for bringing up this point on Paper Mario, it's pretty relevant to drawing lines around criticism.
(Game) criticism is not the same as (game) design: While expertise in criticism certainly exists, the fact that criticism is entirely based on reader perception makes the field open to anyone. Furthermore, since it is based on reader perception, the author has no authority over the field. Miyamoto, as a critic of his own products, is not innately qualified by means of his having designed them, and I see no conflict of authority in criticizing a work by any designer.
You can think of it in terms of bug reporting. While it's appreciated when you tell programmers that their code doesn't work, or isn't documented properly, or is unintuitive, it's nonsensical to tell them that they don't understand OOP. ("Let me disagree slightly with your analysis of OOP, even though I don't know any CS...") To criticize a product is fair game, to criticize an expert's knowledge is not.
I think it’s also important to draw a line here: Price has no duty to the community on her personal time. Community Management is a job, not a lifestyle! I agree that there were better ways to approach the situation *if she wanted to help the community*, but she made it clear that she wasn’t doing that on her free time. I do see why you might act differently in the situation, but many (including me) aren’t interested in doing what is effectively unpaid work off the clock. And not all of us actually like the community that much in the first place!