Is killing people because you hate and fear them a terrorist offence? It would depend on the motive of the perpetrator, I would suggest.
Admittedly, this is rather nuanced.
If you were Muslim, do you think calling this a terrorist attack is appropriate?
It would appear to raise the status of the perpetrator if his motive is not self-evidently sophisticated enough to considered a terrorist act.
If A kills B because he hates him, is it a terrorist act? I would say not.
If A kills B because he hates him and his family, is it a terrorist act? I would say not.
If A kills B and the people of his race/religion because he hates B and people of B's race and religion, is it a terrorist act? It would depend on what A hoped to achieve by his mass murder. If it was just personal gratification, I would say that in itself is not enough to make it a terrorist act.
I would define terrorism as crimes committed in furtherance of a political cause.
Here is a hypothetical situation:
Someone not known by his friends and family to have converted to Islam gets a gun and a car, shoots and runs over people and is shot dead by the police. He is heard to say"Allahu akbar" by witnesses. Does this mean he is a terrorist? It would appear so, but what if his real motive was to simply run over and shoot people for the sheer hell of it and he only pretended to be a Muslim because it makes him seem scarier and more interesting?
Should this person still be considered a terrorist even if everything he did was for his own personal gratification, including that of appearing to be a Muslim terrorist just to get more column inches and publicity for his suicide?
Abbott: Finsbury Park a ‘Terror Attack’, But Westminster, Manchester, and London Bridge ‘Incidents’
Apparently, being a victim of a terrorist attack raises your status as a victim and raises the status of the perpetrator too.
If we and our loved ones are to suffer death and injury, it seems we prefer to suffer death and injury at the hands of terrorists rather than at the hands of "mere" common or garden mass-murderers.