Covid was years ago. Right now it's tariffs.

If the employees are being paid under the table, they would mean the employers were committing an obvious crime opening the employer to extortion. However, if the employees were Using fake social security numbers, then it would give the employers the benefit of the doubt. It also would mean the employees do pay takes, collected by their employers. From what I’ve heard, the latter is most common.

Most undocumented immigrant laborers actually do pay taxes despite not being able to take advantage of what they are being taxed for (eg. social security).

And there have always been aspects of using undocumented labor that are negative and exploitative and I'm all for the US government making real positive changes in this area, but any policymaker coming at this from a non-racist perspective that wanted to make real changes would do it by fining or charging the people who are hiring the immigrants.

Of course, that's not what the Trump administration has done or will do.

Even if they pay no other taxes, they do pay sales tax on their purchases at stores, gas stations, and so on. And those taxes go to the state or local government, and help pay for school and other services.