The 87,000 number combined with the "armed federal agent" description is a bit misleading. Looking through USAjobs.gov there are a ton of job openings at the IRS but I'm only seeing 300 open for criminal investigator/special agent job.
Just to be clear I don't support expansion of the IRS.
Below is the job description for the criminal investigator if anyone was curious:
IRS-CI Special Agents (SAs) are duly sworn federal law enforcement officers throughout all 50 states and US territories including special agent attachés located in 11 countries. As a SA, you will combine your accounting skills with law enforcement skills to investigate financial crimes. SAs fill a unique niche in the federal law enforcement community due to IRS-CI's broad jurisdiction of Title 18 and Title 31 crimes, in addition to our primary tax enforcement mission. SAs are known for their financial investigative expertise in areas, such as, tax fraud, public corruption, cybercrimes, narcotics, terrorism, and much more. Today's sophisticated schemes demand the analytical ability of financial investigators to trace transactions through complex financial records.
The following are the duties of this position at the full working level. If this vacancy includes more than one grade and you are selected at a lower grade level, you will have the opportunity to learn to perform these duties and receive training to help you grow in this position.
The Special Agent plans and conducts investigations relative to criminal statutes of tax administration, financial crimes, and other related offenses, which vary in levels of complexity and scope. The majority of the time is spent on investigations involving most or all of the following characteristics:
Indirect accounting methods to establish evidence
Precedent setting legal or investigative questions
Highly complex or unusual accounting problems
Information obtained from diversified sources gathered over a wide section of the country
Interrelationship of facts and evidence that are difficult to identify because of numerous holding companies, entities, etc.
A mixture of legal and illegal activities
Performs other investigative and enforcement duties such as:
Testifying as a Government witness
Assisting the U.S. Attorney during the preparation of case for trial
Conducting collateral inquiries
Providing protection to persons and property
Obtains, evaluates, integrates, and recommends actions on information items to identify larger areas of noncompliance (e.g., major profession, occupation, industry, or wide geographic area).
May serve as a team leader and/or expert consultant in the information gathering function.
Conducts or participates in surveillance, armed escorts, dignitary protection, undercover operations, execution of search and arrest warrants, seizures, etc.
Protects the government's interest in enforcement activities.
Maintains good physical condition in order to conduct criminal investigations, surveillance, protective assignments, undercover assignments, etc.