I agree with you that most of that article is bunk, and I can also say that other events in that century can hold a candle to the assassination. I do agree with you that it was inevitable; you could see the dominoes lining up from as far back as Napoleon if I remember my AP Euro well enough.
However, in defense of the importance of WW I, it was an extreme escalation in the nature of warfare and in the scope and magnitude of its effects in the West, both in physical destruction and the annihilation of the prior western worldview. The assassination of the archduke wasn't the only instigator of the war, but it is widely recognized as the spark that lit the powder. The importance of that war at least, if not that assassination, should not be underplayed by any means.
I wish that class had been more on topic, perhaps more focus could have been given to the wars and less to Ted talks on unrelated mumbo jumbo.
It is a real shame that a lot of wars get skimmed over in history classes considering their enormous importance from just about any perspective.
My High School World History teacher has a poster titled "The Forgotten War" about Korea hanging on his wall; we didn't even cover Korea for a full day in APUSH.