This I do not have a problem with.
It is not a straw man argument, but you just made one.
By design, boxed text is meant to be read aloud, correct? And most of the time, that text is going to be in English. But quite often, your campaign is not being run in English. So you are interrupting your session with reading text aloud in a different language. That is jarring, and one of several reasons I listed for disliking boxed text.
It is a completely fair argument.
That's not what you initially said though. You said that only a small percentage of D&D players run the game in the same language as the text language is of the material in front of them. That's not a fair argument because it goes against everything we know about the game and the players. And if true, then you need to provide some sort of data behind it. Saying "Lots of countries speak languages other than English, German, Spanish, French, Japanese, etc" (all languages the game is translated into) does not mean that only a tiny percentage of players play in countries where those languages are their primary language. Do you know how many countries have English or Spanish as their primary language? It's a lot more than 2, and when you add in the other available languages, and look at where the game has sold, it appears you have it backwards. It's not a tiny percentage who run the game in the same language as the books, it's a tiny percentage of overall gamers who run the game in a different language than what is available in text.
I.e., it's not about the # of countries that don't have one of those languages as a primary language, it's about of all the people who play the game, where do they live. Maybe because we just had an election, but this reminds me of the argument "I won more counties in the US, so I should have won the election." when the great flaw in that is that it's ignoring where the people actually live. How many live in Orange county CA vs Wallowa county Oregon. How many D&D players live in the US, UK, Germany, France, Spain, Mexico, Central&South America, Japan, Australia, New Zealand vs how many live in Denmark, Iran, or Romania? Is it truly only a tiny %?
I don't necessarily disagree with all of your other objections (they are your opinion and preference and are welcome to them). I just can't see the logic behind saying that one of your top objections is that "only a small percentage of players run the game in the same language as it's written."