No worries, I'm no part of the 'toxic assclown' faction on Reddit and always assume commenters to have the best in mind when they answer. It's always nice to come across someone who puts some thought in their words

I don't know what your native language is or where you are from, but I still want to add that I feel like the problem regarding the written language that you mentioned was something I didn't think of. I was talking about the spoken word specifically. So, I guess what you are saying is true, but - correct me if I'm mistaken with this assumption - together with your second point about native speakers correcting each other, I will still argue, that both of those phenomenons definitely happen more regularly when the language in question is English.

Maybe due to it being an internationalized language, so you never really know who you are talking to, unless you are seated square in front of them; or maybe due to English not being coherent regarding its own pronounciation, so people are more prone to point out what they consider to be 'faulty'..? Anyways, I have observed native English speakers doing that to each other quite a few times, while I can come up with exactly zero occurences of this in my own native language, which is German. This leads me to conclude that this happens with differing frequencies, depending on the language.

I personally am under the impression that a lot of that has to do with social knowledge rather than actual knowledge about the language in question, though.

When I say something 'wrong' (f.ex. grammar-wise) in my native language, I do so with confidence. I know what I just said, and you gotta deal with that, full stop. And people will mostly just accept it, shrug their shoulders, and go:

'huh, guess that's one more way of saying it..? Sure, why not? He seems pretty stubborn about it, so I must be the stupid one'.

And when enough people start imitating the word, expression or manner in which you just said something, it will be considered 'in line' or within the range of the acceptable, respectively - others will think 'that guy definitely probably knew what he did there (maybe?), so he must be.. uhhh.. fluent'.

The same is not true for a second language, though. Going by my own experiences: as long as people don't see you and thereby aren't able to judge your nationality, ethnicity etc.; given that you speak their language well enough, they will simply assume you to come from a remote enough region that their assessment of themselves being in the wrong (or 'not in the know', rather) will somehow still hold true. When they do see you, however, they won't accept nothing they'd deem 'non-standard', because they will immediately assume that you just don't speak the language well enough.

I've found myself in this very situation several times, one of which even cost me a job interview, because the lady on the phone simply refused to believe me when I told her that I'm German and therefore didn't have to jump through some of their hoops regarding providing proof of language proficiency. That might sound like anecdotal evidence, but I'm fairly certain I am onto something with my observations so far

That sounded suspiciously like a summary of something worth a read. Can you recommend some book on that?

I think somewhere in there, there's a point to be made regarding the frequency of colors used in national flags in this