The tiny fine, the minimum available under the legislation, is not designed to punish Facebook or Twitter. This is an administrative process. The infringement of Twitter and Facebook is now a matter of record putting them on notice to comply with Russian legislation or to face the consequences.
Data sovereignty is an important issue for governments around the world. It might surprise many reading this to learn the EU has similar legislation about the issue and that within the EU, some countries, Germany for one, have even more stringent legislation about where data held about its citizens is stored.
This article deals with how the issue affects the UK in the face of its exit from the EU but indicates the issues and solutions currently in place and how they have needed to be altered in the light of U.S mishandling of data that had previously been thought to be safe. https://www.uk.insight.com/en-gb/learn/articles/2018-05-23-why-brexit-and-gdpr-will-bring-data-sovereignty-to-the-fore
The Russian Federation does not trust foreign corporations to handle the data of its citizens safely. The concerns are particularly in respect of U.S businesses but the agreements between the EU and the U.S mean that the EU can not be considered a safe haven for data on individuals using global data-based businesses.
Here's some background concerning the U.S.
The Russian perspective seems to be not so outrageous and is likely to be what other countries will do as well as trust continues to break down between states.