TL;DR: Russian aviation has a lot of problems with laws, standards and their actual implementation. Nobody cares to fix these problems.
The central "metaproblem" is the persistent assumption of uniqueness, one might even call it a quest for the uniquely Russian way of doing things.
It is implemented by approaching every problem as if Russia is the only country in the world, and trying to come with the solution on their own, without paying much attention to established practices everywhere. In essence, it's reinventing the wheel at every step and 9 out of 10 times the wheel ends up being oval (if not square).
They have a unique set of flight regulations that does not match anyone else's so the pilots have to learn them before they can be hired by domestic airlines. They _still_ don't require all ATC's to speak English, even after that was mandated by ICAO 10 years ago. (New ATC's are taught English during training, but requirements are waived for preexisting workers in smaller airports.) They have a ban on foreign pilots that they are considering lifting, but it's still unclear how many foreign pilots would actually want to learn Russian regs and Russian language as a condition of working there.
In this crash, before the dust even settled in Kazan and before a single bit of data was extracted from flight recorders, there was already a legislative attempt in their Parliament (Duma) to ban domestic airlines from using 20+ year old aircraft. And now we even hear talks about requiring airlines to own their own aircraft. All this happens while there's still no evidence that there was anything wrong with the plane, without paying the slightest attention to the experience of Western countries. (Of course, experts generally know better, and MAK even released a statement in opposition, but it's not certain if anyone in the government is going to pay attention to experts either.)
Part of the problem is the general disrespect towards foreign experiences in particular and foreign countries in general, especially the "capitalist countries" and especially the Great Satan himself, the USA. If you want to turn Russians strongly against something, all you need is to tell them "this is the way they do it in the United States".