I think it is really interesting to deconstruct this. Most European languages have gender as a more central concept in the language; as the author points out "In Spanish, if referring to a group of friends containing both genders, you would use amigos, clearly favoring the masculine form". It seems like these languages would be even more clumsy around these non gendered cases!
Perhaps not having gendered nouns causes other gendered grammatical constructs (in this case personal pronouns) to stand out more. Do speakers of other languages with gender as a key construct see changes happening in those languages to make the language more gender neutral or does the high prevalence of gendering make that too intractable?