I also found that strange but I looked it up and found CDC Brief Summary for Clinicians: Evaluating and Managing Patients Exposed to Birds Infected with Avian Influenza A Viruses of Public Health Concern:

CDC recommends that people with these exposures monitor their health for any signs and symptoms for 10 days after their exposure and to call their health department if they develop illness. Health departments may ask responders to seek care and/or testing for avian influenza A virus infection, including specific testing for avian influenza A viruses. [...] If conjunctivitis [eye redness] is present, conjunctival [eye] swabs should be collected.

I'm gonna say this person is a worker at a facility where there is an outbreak. Some kind of ag public health nerd conveyed to the workers that any of a broad range of symptoms (see link) is cause for concern in this context. And this person either out of obedience or fear of disease or hoping to get some paid time off did as they were told, went to the ER or a walk in or whatever where a swab was done.

Basically, at least a few people did their jobs by the book. (Forgetting about the broader situation of the business.) It makes sense to have a lower threshold to to test in a very small number of the highest risk people.

Okay... So, the person was working with dairy cows. A person working around dairy cows spends WAY more time in close contact with them that a person working around beef cattle.

There's ALL sorts of shared infections that cows can get and spread to people and people can get and spread to cows. So things like, just general staph infections and pink eye are not uncommon.

Best guess, is that a person working around the dairy cows thought they might have got pink eye or a staph infection in or around their eye and were smart enough to go get it checked out. The docs were smart enough (or maybe there's a mandatory testing/reporting like there is for stuff like Rocky Mountain Spotted Tick Fever) to check for a range of diseases that can/do jump species.

The article is unclear if the patient was found to have live virus or if there was just some immune system check that showed a past exposure to the bird flu.