HN on aggregate tends right libertarian, which is politically neutral with regards to the usual US "libs vs conservatives" political dialog. For every socialist I can show you a dozen Georgists, for every anarchist I can show you a dozen "anarcho-capitalists". There is some general resentment against concentrations of power (e.g. lobbyism favoring large corporations) but an unquestioning faith in the systems that bring it about (i.e. "small government" and "free markets"). There is lively debate around topics like Elon Musk, cryptocurrencies, online censorship and protectionism vs free global trade, but all of this happens through a lens of right libertarianism.
However this also means you will see literal nazis, white supremacists, antisemites, eugenicists, Christian fundamentalists and so on promote their beliefs (and attack others with different beliefs) here. And the people promoting these beliefs have become more open about their stances over time while simultaneously rarely being flagged/killed as long as they can stick to an acceptable register of seeming respectability (e.g. using the trappings of scientism by citing pseudoscience or flawed statistics to support their arguments).
The synthesis of progressive and reactionary is always reactionary because the latter actively relies on dishonesty and deception to propagate itself. An "open marketplace of ideas" will always favor those willing to game the system instead of playing by the rules.
I used to believe that "rational debate" would solve everything, too, but as the adage goes: you shouldn't try to play chess with a pigeon because no matter how good you may be at the game, it will just knock over all the pieces, shit on the board and strut like it won anyway. If you are debating the existence and value of humans, you have already ceded ground to the side that wants them extinguished or silenced.
Note that at no point am I alleging that Dang is reactionary or an "SJW". Much like HN on aggregate, he is a right libertarian: progressive on some civil rights issues, conservative on others but generally in support of free markets and "free speech" as long as it doesn't contain any slurs, explicit insults or direct threats. In his comment he points at the language from "both corners" and shows how similar it is and concludes that if "both sides" are equally upset, he must be doing things right. To play the same rational debate game, this is a well-known fallacy in action: https://en.wikipedia.org/wiki/Argument_to_moderation
If one side argues that people in economically precarious situations who are members of a demographic that has traditionally been discriminated against and actively disenfranchised should receive more support to compensate for the historic injustices and the other side argues that demographic is biologically predisposed to violence and low intelligence and should be treated as dangerous and unfit for skilled labor, "upsetting both sides equally" doesn't mean you've hit a golden mean, it means you've ceded ground to the latter group.
Finally, note that I've said there's a "reactionary political bent on HN". This is what I mean. I'm not saying "HN is reactionary", I'm saying, on aggregate, HN leans reactionary more than progressive, qualified by what I just described about "free debate" and false middles. This is different from Twitter, for example, which since the buyout has demonstrably shifted to reactionary because many progressive liberals and leftists abandoned the platform after it became clear that there was no more interest in moderating even literal nazis. It's also different from 4chan, which at some point was so overrun by "ironic" nazis that it's now impossible to tell what any of its users genuinely believe although in terms of what they say the general tendency is to the far right of almost any political point of reference.