Domestic terrorism in the United States consists of incidents confirmed as or suspected to be terrorist acts. These attacks are considered domestic because they were carried out by U.S. citizens or U.S. permanent residents.That is how its defined in the US by code of law. This is how its defined in the rest of the world...again via Wiki...
Homegrown terrorism or domestic terrorism is commonly associated with violent acts committed by citizens or permanent residents of a state against their own people or property within that state without foreign influence in an effort to instill fear on a population or government as a tactic designed to advance political, religious, or ideological objectives.Its nuanced but the details make the difference.
The incident in California cannot be called domestic terrorism if it can be reasonably assumed that the terrorists were influenced by ISIS.
So FUCKINIG STOP calling this domestic terroristm. ITS NOT. This is plain and simple terrorism. ISIS successfully hit us. Deal with the reality and stop playing word games!!!
NOTE: After thinking about this a bit more not only is this terrorism (without the caveat of being called "domestic") but it also bears all the hallmarks of "Insider Attacks" that our forces experienced in Iraq/Afghanistan. So called naturalized or 2nd gen citizens that go on a rampage on behalf to ISIS? Yeah. A terroristic insider attack is a much better definition of this and the Boston Bombing.