Why do you need it?

Decades of muscle memory is hard to overcome?

If I were the author I wouldn't bother implementing the option for that reason. I was curious whether it was due to a genuine accessibility reason, like using a device other than a mouse that makes it really hard to adjust.

Yeah I'm sure those 4 lines of code are a big ask.

Just to defend the OP, it's that extra UI (and small niggle of confusion) that are the bigger ask.

<button class="closet-camera" id="closet-camera" type="button" aria-label="Invert camera">

  <svg class="cf-ic" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><polygon points="21 4 3 4 10 12.4 10 19 14 21 14 12.4 21 4"/></svg>

  <span class="cf-tx">Invert camera</span>

  <kbd class="cf-key">I</kbd>
</button>

They’re free as in puppies!

You haven't walked behind them picking up their poop have ?