1. These missile, acquisition and tracking systems are complex, with lots of integration and communication involved. "Militia" can't even begin to do this, even with a little training. Rooskies did this, not necessarily targeting an airliner, but they are in it up to their tits. 2. Someone will be very sorry they f'd up. Probably a lot of someones as this is a total disaster for Russia. 3. The Euro's are stuck in the Neville Chamberlain mode, I hope this wakes them up. You would think they would learn from history, but they don't. 4. Still kinda like Putin, but he is pretty much a turd! He is not swayed by talk, but action gets his attention.
It makes no sense that an airliner would be deliberately targeted. It has to be a colossal boo boo unless the Russians did it on purpose to try to blame it on the Ukrainians or the Ukrainians did it hoping to blame the Russians and turn world opinion against them.