I really wish people would actually research these claims and not just believe whatever some talking head on television says.
CDC: "Because some of the symptoms of flu, COVID-19, and other respiratory illnesses are similar, the difference between them cannot be made based on symptoms alone.
Testing is needed to tell what the illness is and to confirm a diagnosis."
The above would indicate a test CAN tell the difference.
University of Nebraska Medical College:
Did previous PCR tests confuse COVID-19 cases for influenza cases?
Not at all. "The reported numbers were based on highly accurate laboratory tests," says Dr. Broadhurst. "The original test could detect the presence of SARS-CoV-2 with very high specificity," – meaning the test does its job very well.
To make it easy for people to "do their own research" here's the link to the above:
https://www.nebraskamed.com/COVID/p...l-the-difference-between-covid-19-and-the-flu
For the numerous other results disputing your common knowledge (people can commonly be very wrong on a variety of subjects" here is the google search term I used: can test determine between flu and covid
Feel free to check the facts.