The fact that Dogecoin isn't deflationary doesn't mean that it's the same with fiat. In fiat, an entity decides the inflation rate, but in Dogecoin it is standard, which is 10000 DOGE every block. What you don't like is that they're both inflationary, but remember that they differ.

You don't have to read anyone's law; just use your common sense. A currency that has a fixed amount of tradable units is being adopted by more people overtime. So, while the supply increases slowly, the demand increases rabidly as a way to escape the traditional financial system.