Silicon Valley is the new home of censorship. 

Via 9to5 Google: 

There are hundreds of thousands of apps on Google Play which reach millions of users. With that in mind, Google has a developer policy in place to restrict what can and cannot be downloaded from the Play Store. Recently, the company has updated that policy to restrict cryptocurrency mining apps, among others…

First spotted by Android Police, Google quietly added these policy changes without much notice. One of the most notable changes here is a ban on apps that are designed to mine cryptocurrency...

Another notable change here is to ban applications which promote the sale, manufacturing, or modification of firearms, explosives, and ammunition.

We don’t allow apps that facilitate the sale of explosives, firearms, ammunition, or certain firearms accessories.

Restricted accessories include those that enable a firearm to simulate automatic fire or convert a firearm to automatic fire (e.g. bump stocks, gatling triggers, drop-in auto sears, conversion kits), and magazines or belts carrying more than 30 rounds.

We don’t allow apps that provide instructions for the manufacture of explosives, firearms, ammunition, restricted firearm accessories, or other weapons. This includes instructions on how to convert a firearm to automatic, or simulated automatic, firing capabilities.

Read more here.