The independence of infrastructure is the stated goal. But I doubt it's the main one. They've been trying to shut down opposition political commentary[0] by forcing them to move outside of the .ru domain. The next step is to limit the access to non-ru TLDs since they can't control those.

[0] For example, grani.ru had to move to graniru.org several years ago, which was then blocked by most ISPs in Russia due to a government order:

https://grani-ru-org.appspot.com/wiki/Blocked/