We need some objectivity here.
Their is no evidence that either the separatists nor their alleged Russian sponsors are responsible for this, and any reports by OSCE observers need to be taken within the context of their agenda, they are not as many imagine totally unbiased.
I would also take with a pinch of salt the reports of drunk separatists shooting their guns whilst swigging from bottles as they loot passenger belongings. Somebody is pushing their agenda it seems.
We even have the US arguing (quite rightly) for a full independent investigation and then in the next sentence stating that this was the fault (indirectly or directly) of the Russian Federation.
What we don't have is any facts.