In short, this is Google's policy on user data:
You must be transparent in how you handle user data (e.g., information provided by a user, collected about a user, and collected about a user’s use of the app or device), including by disclosing the collection, use, and sharing of the data, and you must limit use of the data to the description in the disclosure. If your app handles personal or sensitive user data, there are additional requirements described below. This policy establishes Google Play’s minimum privacy requirements; you or your app may need to comply with additional restrictions or procedures if required by an applicable law.The Google Play Store has a ton of apps and games that don't conform to this policy, so Google is now stepping in to either force developers to do better or to remove them from the store completely until they resubmit a product that's in accordance with Google's policy.
Content creators of offending apps and games on the store received the following message announcing the upcoming purge of the Store (via The Next Web):
Speaking to The Next Web, the developer behind the popular game Hip Hop Ninja expressed his relief after hearing about Google's intentions for the store:
I think it’s fantastic, this will clear the Google Play store of so many junk and zombie apps that our games will find increased visibility on the store as the search terms will become much less cluttered.
This will make it easier for people to be able to find our app’s like Hop Hop Ninja! with better keyword searches like ninja or Nerd Agency and find much more relevant results. (A previous pain point of developing for Android).
This highlights one of the downsides of releasing games on the Google Play Store; the market is completely saturated due to the thousands of clones of popular apps fighting desperately for a piece of the pie. With less apps around to clutter the store, it becomes easier for quality stuff to rise to the top of the charts.
Developers who received the warning have until May 15 to comply until Google takes "administrative action" to limit the visibility (and thus findability) of their apps on the Google Play Store, possibly ending in the removal of the app.