Last I read the BUK missiles were probably captured from an Ukraine military base?
+ the whole thing was an accident.
Civilians die in war all the time. How is this so different?
The US has suplied Syria rebels with arms and god knows they killed civilians.
It's different because even if the BUK was indeed captured from Ukraine (which is definitely not clear), the rebels would never have been able to capture it if Russia hadn't continually provided support and manpower. This whole crisis was created by Russia in the first place, it was Russia that escalated it, and it is Russia that keep it going by supporting these rebels. If Russia would just have backed off and let a sovereign country make a decision on what economic and political bloc it wants to be part then none of this would have happened.