I’m sure the standard are different for every machine/lab. The whole point of PCR is to amplify genetic sequences and inform you of the presence of said sequence or not. It doesn’t say anything about viral load and no medical professionals are using PCR that way- it’s simply a rapid and cheap test that gives doctors an idea of whether someone may be infected or not. I think it’s a bit disingenuous to say that PCR tests are being using to amplify insignificant viral loads to tell patients “you’ve got the covid!” when that isn’t their purpose at all.

I haven’t seen or read any papers on exactly what viral load determines symptomatic vs asymptomatic vs early infection, but the amount of virus you have changes with the course of infection. So I’m not quite sure where you’re getting the idea that PCR mainly serves to amplify asymptomatic viral loads, since this likely differs for various patient demographics. I think that it’s important to rule out false positives, but detecting and treating early infections is important as well.