I'm certainly not going to defend your teacher or your experience, especially at the high school level. That's too soon. And I also remember being indignant for a similar experience in analytical chemistry.

But... there's a point in one's development as a science student, where science becomes more nuanced than "doing your best and honestly reporting what you observe." Those things will always be there of course. But in an experimental science, doing an experiment and getting accurate results is a vital skill, or you'll never make progress.

Naturally you have no standard for checking a measurement whose result is truly unknown, but you can insert the equivalent of breakpoints where you make sure that the same data do reproduce known results. Ironically for the discussion here, those are called "gravity tests." Students need to know at some point if they're going to like the experimental side of science. Getting things right is part of it. Some people don't belong in the lab.

I happen to be stuck at the "gravity test" level in my day job. My experiment produced a calibration that's reproducible, and that I could use, but it doesn't make sense. I'm not going to move forward until it does.

The problem with a lot of teaching is that the purpose of the lesson is never explained, and the nuanced view is never spelled out.