[nsonha]

Like stated in another comment, it's not about politeness, it's about constructive discussion, you present rational arguments and that only. If someone's position is abhorrent, no matter how they sugarcoat it, people should be able to tell

[zemo]

except that's not at all the case for two key reasons, and possibly more: for one thing, the core of your argument relies on the assumption that participants should be able to tell, but the only way to separate information from disinformation on a topic is if you're already educated about that topic. The alleged purpose of this discussion board is for people to become more educated about the topics we're discussing. If we assume that everyone is coming to the table already educated on the topics, what we're saying is that this is a space where beginners do not belong, and that this space is not an entry point for the industry. A space that is not welcoming to the uninformed is not a welcoming or friendly space, it is a hostile space.

The second major way in which this concept collapses is that HN has a dangerous addiction to labeling things ad-hominem attacks. If someone makes a horrific argument, and you say "that argument is horrific and leads to harm being done to others", you are in every case met with responses along the lines of "that's an ad-hominem attack" or "that's politics this space isn't about politics". HN posters time and time again fail to separate the argument being made from the person making them.

[throwamon]

It's not about being educated on a topic, it's about being good at reasoning (and as a consequence being able to spot bad reasoning). It's also about being curious and doing your own research when you see people talk (and disagree) about something that interests you. This is a much more general set of skills that anyone should have and it takes a lifetime to develop. There's no way around that.

> this is a space where beginners do not belong

Not true at all. There's a lot of introductory material hitting the front page every single day here. If you ask a technical question there's usually someone VERY knowledgeable who will be more than happy to teach you some things and point you to further guidance. I often see two people disagreeing about a topic they both know WAY more about the topic than me. What am I supposed to do? Tell them their knowledge is unwelcoming to me? No way! A level-headed dialogue between them is about the most productive form of teaching I could hope for.

You don't just talk over people who know their shit as if you knew more about it. You present your knowledge (and lack thereof) and ask questions, maybe build an argument. If they're interested in continuing, they will engage in a similar way. I don't see what's so "hostile" about that.

> "that argument is horrific and leads to harm being done to others"

If you just say that and leave it at that, that doesn't mean anything. It's not an ad hominem, but it's not an argument either. If you provide an argument and evidence, you should be taken more seriously. I can tell you I've seen A LOT more ad hominem attacks being labeled as such than actual arguments. What commonly happens, though, is a commenter mixes both a good argument with an ad hominem (or some other fallacy), and then others focus on the fallacy and not the argument. Of course that's bad, but it's all the more reason to not be fallacious.