They're right. Try to find a Dutch IT person with a laptop not set to English. Only a small fraction will realise you can set more than one language and put Dutch as a second, even though many struggle beyond basic reading comprehension in English. They're not picking it because they're just as good, much less better, at English compared to Dutch
We definitely pick languages that work as opposed to languages that we speak. Setting it to Dutch is just worse: UX doesn't fit, english search results wouldn't show up (way fewer results/content/info), and translations often don't make sense (imagine a button called "you shut it" on a modal window, it's a literal translation of one interpretation of the string "close it" but you'll be confused as to what that button will do)
We definitely pick languages that work as opposed to languages that we speak. Setting it to Dutch is just worse: UX doesn't fit, english search results wouldn't show up (way fewer results/content/info), and translations often don't make sense (imagine a button called "you shut it" on a modal window, it's a literal translation of one interpretation of the string "close it" but you'll be confused as to what that button will do)