There's nothing complicated about this. Its very simple in fact.
But I'm happy to go with the definition you posted, I am questioning the way you are using it - with unsaid insinuation and subtext. So let's go to the details.
That was a US federal definition, I actually dont wholly agree. Here's the one that makes most sense to me.
The use of force which targets civilians for political, economic, religious, social or military aims.
As 'unlawful' is almost meaningless when states can create laws to justify violence.
So, if we presumably object to terrorism as defined above, it is on moral grounds, and morality must be universal or it is meaningless, regardless if it is committed by state or non-state actors.
In no particular order:
Hamas rockets in Israel - terrorism
Fatah suicide bombs in pizzerias - terrorism
Hezbollah assassinations of politicians - terrorism
IRA bombing off-duty soldiers in Birmingham - terrorism
Basque letter bombs sent to councilors - terrorism
Paris, Mumbai, London, Madrid - terrorism
Israel bombing of Gaza, Lebanon - terrorism
Turkish attacks on PKK politicians - terrorism
Death squads in El Salvador - terrorism
The Blitz - terrorism
Firebombing of Dresden, Hamburg - terrorism
Murder of civilians on Bloody Sunday - terrorism
Shelling of Grozny - terrorism
US/UK bombing of Belgrade - terrorism
Hiroshima, Nagasaki - terrorism
US in Vietnam - terrorism
Shock & awe and invasion of Iraq - terrorism (you supported this one IIRC?)
You can argue about the severity of each act, the possible justifications, extenuating circumstances etc. Obv state terror tends to be on a much greater scale, but the principle is the same.