If you read my commentary, you'll see I certainly wished a wider range of non-English language films had been included, and I pointed out a number of titles. But yes, perhaps inevitably, English speaking (especially American) films dominate the list. I'm not sure that invalidates the list. I know those contributing value non-English language cinema too, so perhaps they simply felt (in most cases) that the English speaking films were objectively greater. Or perhaps they just preferred them. Again, I discuss the difficulties of separating "greatest" from "favourite" in my introduction, but I do accept English speaking nations are likely to gravitate to English speaking films.
If you are able to point me in the direction of non-English cineastes here on Medium who would have been good people to ask to vote in this poll, please give me their names, and I'll happily include them next time I conduct such a poll. Apart from anything else, I'd be curious to discover their articles. :)