Not all issues/threats are physical/tangible. For example, did you know that there is a casus belli between two NATO allies since 1995? No?
Can you guess why?
Now, if Greece had assurances like Ukraine that half the world would jump to our aid to protect us, we might have done that legal extention as well (Libya just did something similar and “the game” in the Meditteranean is on, again - which I am fairly certain was not in any news you watched in the past week 
), but we don’t. EU and NATO are just pretending that we are all jolly good and having fun (while both sides are drowning in debt to buy more weapons and ships and submarines 
), but it is a bit too much to go around happily and pretend that somehow a casus belli fell from the sky in any case and place in the world.
You might not know about those conflicts, but they are very much real. Exactly as you didn’t know this about Greece and Turkey, similar conflicts exist elsewhere (multiple in the Middle East, Ukraine, Caucasus, Kosovo, South Morocco, Syria, South Sudan, Erithrea, Kashmir and the list goes on and on and on), that are currently on various stages of escalation or de-escalation.
And yes I do not know much about them either, but that is the reason I try to keep my texts/statements away from expressing “oversimplified certainties” or refrain from making statements at all. The media have an obligation to make money and generate clicks. We, as citizens, have an obligation to filter what we learn from the media and, if we are really interested in the matter to have an informed opinion about it, look deeper into it.
Who is the head of state in Russia wouldn’t really matter at this stage. I know that it is more sensational for the news to create a scarecrow, but that war would have happened even if they had somehow elected Borat for president.
Ukraine joining NATO is/was a known and complicated casus belli in the region (which had already been destabilised in the past decade) and that place was a gunpowder keg. We can sit here and pretend that it was a sunny daisy field with cows and “suddenly the fire nation arrived”, but with all the political unrest, the Crimea anexation and the subsequent conflicts, that was not the situation, sorry. It was just not “newsworthy” yet, so, just like the previous examples, most people didn’t notice nor care about it.
Something might go wrong tomorrow in the Balkans ( historically the powder keg of Europe) and I could end up on some mountain-top trying to defend myself with a rifle that doesn’t shoot straight. The idea that while we will be in some trench getting shot at, people would go from their coutches “ayo! they are fighting over nothing” while pretending to care about the outcome like it is a football “our side vs the other side” derby, sounds nasty to me.
We poured a few thousand posts on the issue here, let’s not repeat all that (feel free to read them over):