No not all swabs were positive for covid19, but some of the ones that were positive were used to genetically sequence the virus to see if perhaps if the sample happened to be new strain/variant of covid.
That's what the tweet is referring to, sequencing the virus not the person.
Now there's some truth to the conclusion that the OP was making, swabs are being sold to third parties for who knows what.
No not all swabs were positive for covid19, but some of the ones that were positive were used to genetically sequence the virus to see if perhaps if the sample happened to be new strain/variant of covid.
That's what the tweet is referring to, sequencing the virus not the person.
Now there's some truth to the conclusion that the OP was making, swabs are being sold to third parties for who knows what.
Here's an article. https://www.thelondoneconomic.com/news/covid-testing-firm-selling-swabs-carrying-customers-dna-to-third-parties-301236/