My impression is that yours is the consensus view in the medical community. But I think that what all these people are telling you is that they'd much rather have a much higher chance of a false positive stage 1 diagnosis than even a much lower chance of false negative diagnosis until they're at stage 4. And any positive result from this would obviously be couched in a doctor consult saying "if you have cancer, which this test doesn't definitively show, it's still very early, we're just going to keep an eye on it, we didn't get any confirmation from a chest x-ray or CT", etc

And having a memento mori can be a positive thing.