Just because they are going to legalize it (we still don't know for sure whether the news article is correct or not), you can't go overboard and say that the Russian government has suddenly turned pro-Bitcoin. Like every other government around the world, the Russian government is also afraid of the digital currency, as it can harm the Ruble.
Bitcoin is the new official currency of Russia!
Russia embraces Bitcoin as their new official currency! To the top with this.
When they have a exchange they can directly monitor the flow of Ruble to Bitcoin and also how much money people have.
They can also identify the Bitcoin users, like the USA have done with the exchanges and the KYC/AML regulations. In essence they are invading the privacy of their own citizens, by doing this.
Governments do not like the anonymity aspect of Bitcoin... They have to be in full control, or they will ban it.
Yes, Bitcoin would be legal in Russia, if you give them full control and expose your identity. We have just given them another tool to spy on their own citizens.
Like I previously stated this is better than making Bitcoin illegal. Essentially they could legalize Bitcoin in addition to building their exchange. Nobody is forcing anybody to use that exchange though.