Edit: I went reading. If you didn't get a padron (local residency certificate for your municipality) and hadn't formalised your status before brexit, (which, if you were working cash in hand is very likely), you would be behind a wall of prove-it processes which are based in paperwork, in Spanish. Where's your spanish drivers licence. Where's your tax file number. Where's your pre brexit registration. Prove you've been here.
Various expat assistance agencies have spent months offering people $ services to help them get through, including handy advice like be polite and dress smart and don't shout at the officials..
The overwhelming majority of longterm residents will have gone through the steps. The newspaper story is about the people who were never going to get over the line I suspect.
My language test theory has little to do with it.