Well, you burn down your own house so that the IRS won't get their paws on it after your successful suicide attack on the IRS building. It wouldn't surprise me if a nutter who was also a tax cheat would be in trouble with the IRS.
Pity that he left a wife and child behind. How horrible that he would burn down his family's house with his family still inside.
Regardless, even though it's too early to tell what happened it's looking less and less likely that Mr. Stack is some jihadi SOB.
The thread I was responding to, suggested his motive was that he was a “Republic of Texas successionist”. I was pointing out, that if he was motivated by a desire for the recreation of the Republic of Texas, why burn your own house. If his beef was with the IRS, then it is pretty obvious why he would burn his own house.