[valdiorn]

Not defending it, but I'm not sure the concept of "right-wing terrorism" was a commonly known concept at the time.

People commit acts of terror for all types of reasons; holy wars, separatist movements and other political movements, etc. There had been attacks and events in the US for similar right wing reasons, but there wasn't really an umbrella term for this type of event at the time. The fact that this motive is now as commonly known as jihad terrorism is, is rather worrying.

[croes]

There is a long history of right wing terrorism, Timothy McVeigh committed the deadliest act of terrorism in the US until 9/11.

In Italy right wing terrorists from the stay behind army Gladio committed several false flag attacks to prevent the rise of communist parties.

1980 a right wing extremist bombed at the Oktoberfest in Munich.

Before 9/11 it was one of the dominant forms of terrorism. The movie The Sum of all fears is bases on the book of the same name. In the book the terrorists are muslim extremists, but they deemed the scenario as too unrealistic so they changed it to Neo Nazis for the movie.