Somebody flipping out, burning down his own house, and taking revenge on the IRS isn’t exactly what I’d call “terrorism” either.
Maybe it’s a distinction without a difference, but when most people think of terrorism I’d guess they’re thinking of actions done on behalf of some organization with political objectives, moreso than some “lone nutball” who goes postal because he thinks the IRS screwed him over.
Let’s make a bet on how long before someone from the white house calls it an act of terror...of some sort.