Of course, the DoJ didn't bother until someone tried to impersonate the IRS.
The IRS doesn't want the competition.
Most of the scam complaints go to the FTC, which is supposed to enforce the ‘Do Not Call’ list but does nothing. Some of these complaints ended up with the IRS, which does care, and which pushed the DoJ to action. If it was up to the FTC, nothing would ever have been done.
Amen. Too bad the LEO’s didn’t go in hot and heavily armed, and detect some minor “resistance”. I would be angered and upset over that for about, oh, .0001 seconds.