Are spelling correction PRs not welcome? I'd never put it on a résumé but if I'm following a README and I see a typo, I'll generally open a quick PR to fix that. (no automated tools, not scanning for typos, just a human reading a README).
I think a true spelling correction would be welcome. But I think the kind BS attitude the GP is describing often leads to useless reformatting/language tweaks, because the goal isn't to make the repo better, it's to make a change for making a change's sake with as little effort as possible.
On the flip side, I used to get a lot of spam PRs that made an arbitrary or net neutral change to our readme, presumably just to get "contributor" credit. That is not welcome or helpful to anyone.
I always find it a pity when someone has been clever and it's missed. "Spelling incorrection", get it? It's not a correction. It's the opposite.