After writing the comment on the question, it got me thinking about this more generally:
Suppose this site is not for ESL questions. How, then, are you actually going to discern "ESL questions" from other questions? I think it's not always clear-cut at all.
It would indeed be easy to simply look at the user who asked the question, and if English is not his/her first language, declare the question as "ESL question" and be done with it. But that would be idiotic. (If someone should disagree with this, I can add examples.)
Or should questions that are about learning English be flat-out disallowed? Well, isn't learning (more) the point of every question on a Q&A site? Disallow only questions that are somehow "too basic"? That sounds about right, but it will be difficult to draw the line, or to formulate a rule about what questions are too basic.
Perhaps it's best to leave this to the emerging community to jugde on a case-by-case basis – if a question seems inappropriately basic for this site, people will downvote it or vote to close it.