The social network explained in a post on its developer blog that it implemented the change to ensure that users don’t see like buttons or like stories where they shouldn’t, saying:
Currently when you point a Like button at a URL with the proper metatags, we create an admin page through which you can establish the same age-gating controls that are available to Facebook pages. These controls prevent us from rendering the like button and presenting the resulting story back to the wrong audience. For example, this functionality allows a beer company to avoid presenting a like button or like stories to people who are not allowed to see alcohol-related content.
Going forward, in order to limit the distribution of these stories to people in the appropriate country or age group, you must include a metatag on your URLs indicating the restriction. Please review our documentation on how to do this.
If you previously used the like button and an admin page as a way to gather and publish to fans, you will no longer be able to. Instead, you should create a Facebook page and update your like button to point to that page. People who select the like button on your URL will then become fans of this page and are eligible to receive page posts from you.
You must implement metatags on your URLs in the next 90 days in order to continue age restricting the like button on and post from your app. We have updated the platform roadmap to reflect this change. To help you make this change, we are launching a migration setting in the dev app. To learn more about how to use it, please read the following developer doc about the like button migration.