Like any other organization, the IRS has judgment calls to make about its priorities.
In the Greek myth of Orpheus and Eurydice, the musician Orpheus descends into the realm of the dead, trying to save Eurydice from a lethal snakebite.
There is a big difference between intentional tax evasion and honest mistakes.
The phrase "tax audit" generally carries the same type of connotation as "root canal." Almost by definition, it's not very pleasant - or at least that is the popular perception.