First of all, it's about an entrepreneur traveling to the US for a startup, which is directly relevant to a significant proportion of YCombinator founders themselves.
Beyond its direct relevance to the core founding audience of HN, it is not clickbait or wantonly inflammatory, and is clearly of interest to many based on the comment activity and votes.
Another commenter (now deleted) made the claim that, saying an issue shouldn't be partisan is “just saying ‘everyone should believe what I do’ but in the lexicon of people who look down their nose at the general public.” They added, “The only nonpartisan issues are the most basic of things that all societies have like ‘don't murder people’ (but even then the minutia become debatable).” Although the comment has been deleted, I think this merits a little further exploration, because it's a widely held viewpoint, and there is some truth to it, though I disagree more than I agree.
There are definitely people who mean, "Shouldn't be a partisan issue," that way, but what I mean when I say it is that from the clash of opposing opinions comes the spark of insight, and partisan struggles in which arguments are soldiers do not permit that process to happen: https://slatestarcodex.com/2014/02/23/in-favor-of-niceness-c...
I have frequently observed variants of the following exchange in mathematics classrooms:
Professor [writing on blackboard]: So you see that this just reduces down to x² + a.
Student sitting in the third row of the audience: No, it's x³ + a.
Professor: Hmm. [pauses]
Student: Because the x from substituting f doesn't cancel.
Professor: Yes, you're right. So you see that this just reduces down to x³ + a.
Sometimes it goes the other way, and the student is the mistaken one. Neither participant goes into the discussion on the premise that "everyone should believe what they do"; rather, they believe that by discussing the issue they can arrive at an agreement, which may involve changing their own mind. Converting the discussion into partisan struggle prevents that from happening. Imagine what would have happened in my example if the discussion had instead gone as follows:
Professor: So you see that this just reduces down to x² + a.
Student: No, it's x³ + a.
Professor: I don't remember paying tuition to come and see you lecture.
Or, alternatively:
Professor: So you see that this just reduces down to x² + a.
Student: You didn't even do a modicum of research. It's x³ + a.
Or, how about this?
Professor: So you see that this just reduces down to x² + a.
Student: No, it's x³ + a.
Professor: You're being manipulated into thinking that this factor is being canceled incorrectly by the horrible evil professor.
Or, how about this?
Professor: So you see that this just reduces down to x² + a.
Student: "x²" ? Êtes-vous fou ? Restez avec x³ !
This difference comes out in its purest form in mathematics, but it's also possible for discussion and consultation to reach agreement on empirical and even moral issues. But partisanship is an obstacle in that process.
For example, that time when English people in England didn't count: https://en.wikipedia.org/wiki/Englishry