> Also unmentioned is the very real negative externalities that IRS audits cause. Audits disproportionately affect poor people [2], who are also the least able to spend time dealing with them. The United States already has extremely low tax evasion rates [3]. Rather than spending money to catch more of the very few cheaters by audits, other country's tax authorities have found "nudge" letters were found to be similarly effective and vastly cheaper.

That's not a strong argument against audits. I'd just take that to mean the IRS should mainly audit people or businesses based by how large the underreporting was.