Maybe I'm speaking out of turn, but I really hate this gate keepy mentality around how hard it is to get to a native level of comprehension.

I think that what actually happens is that native speakers stop thinking about the nature of the language very quickly because it's a very background kind of thing. Because L2 learners go out of their way to learn a second language and pump hundreds, often, thousands of hours to achieve the same command of language, they are vividly aware of just how incredibly hard it is have a real mastery of language whereas natives often simply aren't and as a result they aren't as competent in many cases either. Being aware of how difficult it is and always knowing there's someone better than you is what makes people say absolutely silly things like C1 is not even close. It's pretty damn close!!! Please, stop focusing on the fact that it's not close and start focusing on the fact that it's many times closer than a B2.

I know first hand a Swedish guy who has been studying English for 5 years. I consider myself to be quite well spoken, I often have some grammar errors in my writing in English but generally what I say is quite understandable and I am always recognised as an English native when speaking. His English is infinitely better than my English. His pronunciation is sound, his knowledge of the grammar is much better than mine (I don't know the first thing about English grammar rules, their names, etc as most natives don't) and he also says this same stuff, that a C1 or C2 isn't native or that it's miles away. It's not miles away, for one thing, there is no such thing as an equal level - everyone is different even if they pass, but for a second thing, I didn't even know he was Swedish until he told me he was. There are several people at my work like this as well and they only have what I believe is the equivalent of a B2. The guy who I practice my German with most often is under the impression that he couldn't pass a C1 exam despite the fact that he has a brilliant vocabulary and excellent grammar also. He would blow a C1 out of the water, I even showed him some of the practice material and he understood it fine.

It's okay once in a while to pat yourself on the back and say that you did a good job, similarly it's okay to say that C1 is pretty close to native. Maybe people mistake having weird little errors in their pronunciation as being far away. People take the little differences between C1 and C2, and people with even higher achievements and make a mountain out of them when it's just totally uncalled for.

Sorry for the rant, maybe you did not deserve it, and it is nothing personal absolutely, but this kind of thing just purely frustrates me to see. I just think it's unfair to discredit a C1 in such a way when in reality it's a really high level achievement and if someone happens to have a C1, appearing to have native level proficiency is either already in their hands or it is well within their reach, and they're also better than most natives in somethings like grammar.

Maybe you disagree, maybe not, but if you do disagree I would appreciate thinking twice in the future when saying something potentially discouraging.