In the context of my entire paragraph, maybe it's clearer:

(An IP PIN makes it impossible for a paper or electronic return to be accepted by the IRS. Sometimes fraudsters will fake a return to cash out the refund via direct deposit. Your legitimate return gets rejected because a return was already accepted and then you spend months going back and forth with the IRS to get it resolved. If you have the IP PIN, bad actors trying to file a fake return under your SSN will have them automatically rejected. This used to require proof of active identity theft to get, but now the IRS lets people get IP PINs for tax years no excuse required since 2021.)

A return normally only requires name, date of birth, and SSN to file, electronically or on paper. Many of us have lost all of this information in one or more data breaches.

If you have an IP PIN for a given tax year, if a tax return (printed or electronically filed) lacks the IP PIN, or the IP PIN entered is wrong, the return is rejected. The IP PIN is randomly generated each year for a specific tax year. So there's no pattern to predict, and knowing last year's number (if you could compromise a source like a paid accountant that used it on a return) doesn't help you at all with the next tax year.

At that point, a bad actor would have to either create or compromise your IRS.gov account to retrieve the IP PIN or go to an IRS tax center in-person with all of the risk of trying to pass off fraudulent government issued photo identification at a federal office to retrieve it.

But with so many fish in the sea (people who have lost such data in breaches), if a bad actor tries to file a tax return in your name and gets a rejection that there's no IP PIN, your identity is no longer the lowest hanging fruit. Move on to the next name/SSN on your list...