This really isn't a big deal. Doctors know that these pulse ox meters aren't very accurate and use them accordingly. Nobody's changing their plan because you have a pulse ox of 93 instead of 95. They're there to quickly measure big changes that indicate a problem. In other words, they're looking for patients going from 98 to 75, not 98 to 95.
First, let's be clear:
> Doctors know that these pulse ox meters aren't very accurate and use them accordingly
Some doctors know...
> Nobody's changing their plan because you have a pulse ox of 93 instead of 95. They're there to quickly measure big changes that indicate a problem.
Sometimes, perhaps even often, they're used for this. It's one use case of pulse oximetry, and it's an important one.
I read your post as extrapolating general claims from common cases, and erasing the real experiences of people that fall outside of these common cases.
Bias often happens at the margins. That doesn't make it less real for the people who suffer from it, even if most people don't suffer, even if the common cases work well.
It can be hard to see those margins when you aren't in them, but that doesn't mean they don't exist -- they are still worth writing about and trying to fix.