On the topic of PCR tests:

In relation to the "trust science" argument:

It's problematic to assert that "trust science" equals "trust authority" and therefore you should distrust the arguments of scientists. That is the playbook that the peddlers of conspiracy theories and the anti-science crowd use to push their stone age line of thinking.

That doesn't mean that some political groups will not use that argument to discredit their rivals.

If a politician uses that argument we should always take it with a grain of salt but it doesn't mean that on a specific case the argument is invalid just because it is used by someone in that position. I am sure that it is some sort of logical fallacy to discredit an idea because the proponent is not trustworthy (the story of the boy that cried wolf comes to mind).