Even if you change the view to it's mostly the poor who are the tax scammers it doesn't degrade the counterpoints that these auditors were by far mostly going after the middle class and poor -- you're just asserting the poors are *disproportionately tax cheats that perhaps deserve it.
*edit: since my words were take in bad faith
I think you're strawmanning a bit. They're not saying poor people are tax cheats, just that tax cheats tend to be poor. This makes sense for the same reasons other types of crime are also associated with poverty. This is not to say that wealthy people do not also evade taxes, but they do so in ways that are harder to catch and prosecute. You're implying that going after poor people is some sort of classist discrimination but I think it's far more likely that there are good reasons for it.
They wrote a program years ago to data match EITC, little to no extra manpower from the IRS is needed, that is the point.