These illegal immigrants are paying their taxes

The vast majority of them are earning under the standard deduction and don’t actually owe anything. Individuals don’t owe taxes on income under $29.2k and the cheap labor migrants provide mean they often earn far less. Since they aren’t eligible for any refundable credits, this means there’s no incentive to file.

Where they pay their taxes is typically on the consumer end - sales, real estate, gas/utilities taxes, etc.