Even friends have issues. Russia states what suits them. Russia's problems are these things; they annexed Crimea, they are trying to do the same with Japanese islands, and Turkey reportedly is on record for warning Russian planes invading Turkish airspace and did not heed the warnings for months.
Mind you this is New Russia that seeks to re-draw the map by brute force. NATO's Turkey has a muscular military to do what they say and enforce it without question. The problem with Russia's complaint at least on its face is the fact that the world knows, if military fighter aircraft flew in Russian airspace again and again like Turkey put up with the intruding plane would be vaporized if they could do it.
Point being, Turkey and no other country is any better of a partner than the one who claims to be so.
Obviously we can only go by what we are being told, but as I understand it, regardless of who is fighting who, or perhaps especially so, IF the Russian jets crossed into Turkish airspace, AND were asked to get out AND didn't, then in my eyes, Turkey was entitled to shoot. Russia hasn't been very open (again by general reports) about it's activities over Syria and who they are actually bombing (other than they are apparently supporting the Syrian leader) so in these jittery times, any foreign aircraft staying into the airspace of another country, and won't leave after being asked to, if fair game. We in the UK have had to warn Russian aircraft approaching UK airspace, and escort them off, many times during the past year.
This incident was bound to happen, and may happen again with Russian, French, British etc.etc. aircraft all over Syria much as apart from Russia, the other countries are declaring their intentions and flight routes, I think?
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.