Yes, after the recent promotional event at the White House I can easily imagine protecting Teslas becomes a top priority, and that damaging one is punishable by death.
It is unequivocally terrorism to participate in violence against civilians with the aim of causing political change. And it's domestic because it's here. It's definitionally correct.
It is not definitionally correct because when you or I say "domestic terrorism", despite being the same text and same sound, it is not the same as when the administration says "domestic terrorism". All they're saying is that they care to stop people damaging tesla's. Not that they are going to be stopping the dictionary definition of "domestic terrorist"
It is terrorism, indisputably. Arguing other point is relatively inconsequential. But if we were to argue the point, to argue that spray-paint isn't "violence" isn't going to have much credibility when it's perceived to be from the long standing "words are violence" and "silence is violence" crowd. A selective standard is no standard at all. How the spray paint differs is that it is property destruction in service of intimidation toward a political end.
Does that mean that Republicans engaged in terrorism when they threatened to hang journalists, shoot immigrants or Democrats, etc.? Seems like the courts might be overloaded if we redefine every threat as an act of terrorism.