The context should be what the Tulsa Massacre is, what happened, why did it happen, and what were the consequences of this event. The historical context should be the early 20th century.
Vague and lacking facts to teach.
There are two sides to this event and both sides have embellished the truth. The why and consequences are also two sided. This makes the event difficult to teach in a factual way. In the end it usually devolves into arguments about race with no context of the times the event takes place in. Making it less of a factual historical event and more of sociological study of an event in history.
Neither. The Tulsa Massacre should just be taught in its historical context without getting into any of this. A test essay question about this incident should be something like "Explain what contributed to the Tulsi Massacre and what consequences resulted from this event."
So the answer to this can also range in a wide variety of answers answers making it hard to score.
As far as historical significance on the nation it will have very little impact. Oklahoma History class is where it has the most relevance. Contextually it identifies how klanish ok is at the time, and tied into ok's origins as a democrat led state very sympathetic to the Klan and sympathetic to violence supported by democrats who ran the state at the time.
Now its time for the dig: Good thing we have come a long way since then. It will take a century to expel the klan from Oklahoma. Funny thing is we expelled the klan and as the klan left, the state more and more turned red until you have what it is today.
Would that make a good classroom assessment Guns?