Is it a case of I don’t understand Russian propaganda or is it Russian propagandists don’t fully understand the Western mentality or is it a case of the Russians are handling the madmen of NATO with ‘kid gloves’ ?
To begin, understanding the NATO nations’ intelligence agencies are corrupt to the core is as simple as reading up on GLADIO, where false-flag terrorism had been employed to shape the thinking of the Western democracies’ populations; including the bombings and machine-gunning innocents across Western Europe. Should it be a surprise the Russians do not point to this established history in relation to the downing of MH17? Would the outcome of being perfectly honest result in ‘conspiracy’ charges by the Western democracies and possibly banned (sanctioned) websites, for instance RT and Sputnik?
The facts are succinct. There is a preponderance of the evidence MH17 had been brought down by a Ukrainian SU-25 combat jet as attested to by the Russians, who handed the relevant radar data to the Dutch-led investigation. This evidence had been at first stonewalled and finally ignored. Meanwhile (quite sometime later) the Western led investigation produced fragments of a (Soviet era) Russian manufactured Buk surface to air missile. The Russians declassified the Soviet era documents showing that particular missile (custody established by serial number) had been delivered to and should have been in the possession of (post-Soviet inheritance) Ukraine.
Now, where I have a problem with the Russian side is, the Russians finally saying (metaphor) ‘if you want to own the Buk, go ahead, because if you claim that particular missile brought down MH17, Ukraine owns the crime’ (no one is accusing neo-nazi led Ukraine of being particularly intelligent, especially when producing Buk fragments that can be traced directly back to the Ukrainian military.)
Here’s the evidence backed by witnesses on the ground and apparent actual circumstance:
“A Ukraine Air Force military jet was detected gaining height, it’s distance from the Malaysian Boeing was 3 to 5km,” said the head of the Main Operations Directorate of the HQ of Russia’s military forces, Lieutenant-General Andrey Kartopolov speaking at a media conference in Moscow on Monday.
“[We] would like to get an explanation as to why the military jet was flying along a civil aviation corridor at almost the same time and at the same level as a passenger plane,” he stated” 
Here’s the Russian side’s weasel words that follow the Dutch-led investigation producing the Buk fragments:
“I’ll again go back to the beginning. From the very moment of the crash, Russia was very determined to assist in the investigation. That is why Russia was providing all information that emerged about the disaster, including the testimony of the Ukrainian military, since the evidence of a second aircraft in the sky was around at that time. Verifying the accounts [of the incident] is the task of the international investigation.
“Later, more weighty arguments and evidence began to emerge in favour of the scenario of a surface-to-air missile, which, as a matter of fact, was confirmed by an experiment by the Almaz-Antey concern back in 2015. They identified the type of missile — it’s an old modification — the trajectory of its flight and, therefore, the place from which it was launched. This account, as well as the type of missile and the launch site, which were originally established by Almaz-Antey, were finally confirmed by the data of the Ust-Donetsk radar station, which Russia also handed over, and by the debris of the missile found by the JIT, which helped to establish its Ukrainian origin” 
Preceding is what appears to be irreconcilable accounts (noting the second Russian version does not claim placing the SU-25 at the scene was a mistake) if one attributes “including the testimony of the Ukrainian military” to the Ukrainian air force mechanic who defected to Russia, fearing for his life, after overhearing the (just landed) pilot of the SU-25 (the mechanic had armed with air to air missiles) appear to claim he’d shot down the MH17 civilian flight. It is also noteworthy the Ukrainian SU-25 pilot later ‘committed suicide.’  
The Buk scenario creates a picture of Ukraine forces would risk downing their own combat plane in immediate proximity to MH17 at point of destruction. It makes no sense. What does make sense is, the Ukrainian Buk could have been exploded in controlled circumstance to ‘create’ evidence. What also makes sense is, the Russians taking an attitude if the Dutch-led JIT [Joint Investigative Team] wants to claim it was that particular Buk missile brought MH17 down, Ukraine owns the responsibility, so let them. This also allows for a future picture painted it was incompetence, not malice, downed MH17, avoiding the otherwise indisputable ‘act of war’ where the civilian liner had been deliberately destroyed for purpose of falsely implicating Russia. Opening the door for the Ukrainian Buk points to Russia pre-positioning to allow for a ‘graceful exit’ from the crime (assigned to Ukrainian forces incompetence), were the Western democracies ever to wish to mend relations with Russia; nevertheless a case of ‘doing truth no favor.’
Insofar as Western (or Western aligned) intelligence agencies murderous behaviors concerning shoot-down of airplanes, there is a recent analysis of the assassination of Dag Hammarskjold that shares traits with the downing of MH17; the absolute refusal of certain countries (Ukraine re MH17’s air traffic control records, USA re MH17 satellite photos & USA re Hammarskjold’s DC-6 flight) to release records in their possession.