I guess the CDC is full of idiots:
https://www.cdc.gov/coronavirus/2019...iness-faq.html
They provide protocols both for self-screening by temperature check and on-site temperature checks. The WHO also comments at length on monitoring for fever.
If they are confused you can't blame me for not getting it! We can't all be so brilliant. Although I was not advocating for temperature checks, I was pointing out that your logic is flawed (plus you're not really clear on what the checks do? do they catch 1%? 50%?). If the temperature checks did reveal 50% of covid-positive individuals I think they would be worthwhile. Consider for example a community with a low incidence rate where there is say a dentist's office that checks people. That could be worth it even if bringing 1 covid positive individual infects the whole office, although I doubt that is true when employees are wearing PPE. I think the model of layered imperfect protection makes more sense than binary concepts of interventions working or not working or environments being safe or unsafe.
If you're having an orgy and intend on interacting with everybody in attendance, sure, maybe you really need to eliminate every case. Or choir practice might be like that. Lots of other scenarios don't result in 100% infection from one individual, and adding more infected individuals can make things worse.