The IRS is a tax investigation law enforcement. It is usually a good idea to have the entire law enforcement team armed when confronting a potentially dangerous suspect. Let's say the first shot kills the FBI agent, the IRS special agent can use his gun to defend himself, and even possibly arrest the criminal.
The real Gestapo was often not armed. Their main tactic was intense investigation.
Righties think it's perfectly fine for 18 year olds to walk around with AR-15's slung over their shoulders but cringe at the thought of an IRS agent involved in potentially hazardous duty protecting himself with
a revolver under his jacket:
The mindset that faces us all.