I guess I'm extrapolating from my own experiences. I review and merge pull requests on a semi-notable project, and I am often tasked with evaluating changes in unfamiliar areas, which means I am liable to misunderstand the significance of a change (as Noordhuis acknowledged he did, not being a native speaker). I appreciate PRs that clearly explain the issues and lay out their case, and I defer many one-offs that I deem not worth the trouble.
So I sympathize with the guy. All I see is someone donating his precious free time acting in what he believes to be the interests of the project, doing his best to handle issues that he poorly understands, because someone has to do it.
I have actually encountered your spelling mistake example. I dealt with it by asking the contributor to vet the code for other instances of the same mistake. The results were fantastic: the contributor was inspired to find all sorts of spelling mistakes, and include them in the PR, resulting in one big commit fixing dozens of errors.
So you are correct to criticize his dismissive comment, and choice to close the PR. That attitude drives away potential contributors, and also invites misunderstanding (in this case, accusations of misogyny).