I'd agree that's what got the government's attention, but surely if it's against military bases, wouldn't that mean it's not terrorism?

I was under the impression that, by definition, terrorism had to be against civilian/non-military things, with the aim of generating fear, or terror amongst the population.

I remember things like bombs in shopping centres, cars, schools, city centres, buses, venues etc as terrorism, for example.

These people did what? Broke into a military base and sprayed some paint on an aircraft?

That's not terrorism. That's basically just "a bit naughty". Vandalism at worst.

Who decided that was terrorism? Budgie the Little Helicopter? Jimbo of the Jet Set?