We walk a fine line between the needs of the authors and the needs of the readers. While your intention was simply to be honest about your desire for reviews, and while you would probably not have posted chapters without reviews even if you hadn't stated it, the very crux was equating publishing chapters with receiving reviews.
We've had authors who demand a certain number of reviews before they will post the next chapter. We've had authors ask for a certain type of review. We've had authors use polls, or question/answer formats to generate reviews. That's because a larger number of reviews attracts more readers.
However, readers also don't want to be told that they MUST review to see content. They view that as a form of blackmail, and we get extremely incensed emails from irate readers. Some readers don't want to take the time to log in to leave a review, or can't log in because their college or university won't grant access to an adult site. Some readers are afraid to review because they've gotten a bad reaction from another author.
We don't mind an author asking for reviews. In fact, at the bottom of every monthly newsletter, we remind readers to review. Feel free to ask for reviews. What we won't permit is the second half of what you did. It's not an informed choice when the actions of others affects the outcome, since Reader A might review, but if no one else reviews, no new chapter is posted. Don't make it a trade: reviews for chapters. That's not a request any longer. It's a demand, and no matter how we turn that one around and look at it, the coercion is simply not something we can permit.
I hope this clarifies our position, and our reasoning behind the rule.