Sorry, but that's bullshit. Terrorists are people who do politically motivated acts of violence in order to spread fear and terror amongst a populace, hence the name.
The motivation does not matter, the acts of violence are the true crime, and we had laws that forbid all the acts of violence so called terrorists do for ages, there is no need for special laws against terrorist and "regular murderers" and other criminals. What they do is the crime, not why they are doing it.
And it is not just the US that use the term creatively, it is only the US that uses the term primarily to justify wars, because nowhere in the world the military is such a huge economical factor than in the US. They basically need wars for their economy to function.
There are 2 things in this world basically any democratic government in this world uses to silence protests against unpopular measurements, child abuse and terrorism.