I wonder if there isn't perhaps somewhat like an uncanny valley of language, wherein it's even more confusing when someone is using the right words and pronunciation but not quite putting them together in the normal way.
Sort of like the famous Yahoo Answers query: "Has anyone ever been far even as decided to use even go want to do look more like?"
Nah, it is just a way for people to make themselves feel superior. It happens a lot here in America too. I think my english is fine, but say one word just a tiny bit off and some of them will make a "what?" with a face of pure confusion as if you were speaking in a completely foreign language.
My main language is Spanish and when I speak with people practicing their Spanish I can usually understand them no matter their accent or how bad their pronunciation is. It has to be really bad for me not to understand them. The context of the conversation helps a lot too. But here in America say a word a bit off and people make a big deal out of it. C'est la vie.
We have a team of non-native English speakers at my work. Hindi, Mandarin, Italian, Argentinian Spanish, and some wacky english accents like Newfie, Scottish, Irish, German...
After a while they all just become "language" and your mind handles it fine. But new people have such a hard time swapping between hearing the different languages.