I think thats missing the point tbh.
It
is actually the point.
1- If they were after protecting their airspace they wouldn't have shot it
outside their airspace, regardless of whether it entered their airspace for a few seconds or not. They were clearly set on hitting a Russian jet regardless of the circumstances, they hoped to have the "inside my space!" excuse, but they were busted. There is absolutely no reason for them to follow the Russian jet into Syria (even if it "entered their space for a few seconds") other than deliberately trying to destroy a Russian jet, and not trying to "protect their airspace".
2- Hitting it inside Syria does not only prove that they invaded Syria's airspace, but also committed an act of aggression inside Syria's airspace. Now if Erdogan thinks it's unforgivable to enter his airspace even for a few seconds, how about entering Syria's airspace and shooting an aircraft inside it?
3- It is clearly a crucial point which is why Erdogan is still insisting they shot it inside Turkey's airspace, even though his allies have already admitted it was shot in Syria's airspace.
In fact he got so desperate trying to "prove" they hit it in Turkey's airspace, that he resorted to this kind of "evidence"...
But Turkey's President Recep Tayyip Erdogan has repeated Turkey's claim that the jet was in Turkish airspace at the time it was hit in direct contradiction of the US analysis.
He said part of the damaged plane landed inside Turkey, injuring two civilians on the ground.
4- The fact that it was hit inside Syria proves that Erdogan is lying, and actually throws a lot of doubt into Erdogan's whole story of "invaded my space for 17 seconds!", even though the remaining details are less important. What's important is that the only proof we have of a jet invading the airspace of another country, and actually committing an act of aggression in the airspace of another country, proves that Turkey was actually the aggressor.