The logic is strange, twisted, and in an insane and imperialist kind of a way even makes sense.
You can see it in pronouncements by the UK Foreign Secretary that Russia could end the situation in Syria tomorrow and you can see it in this editorial comment on the BBC:
Mr Lavrov’s central message – that Washington has refused to press its allies to separate themselves from the Islamists of al-Nusra ignores the fact that it is Russia’s air campaign that is pushing rebel groups into al-Nusra’s arms. 
Well. The Syrian government (call them regime because we are against them) is bombing groups who are trying to destroy it. Russia is supporting the Syrian government (though to what extent Russia has been bombing groups other than ISIS and Al-Nusra is a matter of contention). If the Syrian government/regime wasn’t bombing the rebel groups then they would have lost the war and been overrun. When the political and media classes in the West say that Syria/Russia shouldn’t bomb the rebels what they are really saying is: give up your arms, lie down and surrender, and the war will be over. That’s true enough. But it is not a piece of analysis. It is a threat and a call for unconditional surrender. When they make statements that Russia is prolonging the war in Syria by assisting the Syrian government the sub-text is: stop doing this, Assad will fall and then there will be no more war. I.e. we will win. To present this demand for unconditional surrender as a piece of analysis is characteristic of imperialist thinking.
They are stilled glued to the dream of regime change.
But Russia is thinking long-term. Russia’s analysis is that if the government of Syria falls then Syria will become another Iraq, another Libya – that is another failed state facing years of turmoil and suffering and providing a haven for terrorists – people who want to hurt Russia. That is why Russia is continuing to support the Syrian state.