Don't overlook the reality of what happened to startup culture:
Early 2000s: Startups were cool but then the bubble burst and they became a laughing stock. Military and defense seemed like "serious" work, and startups like Palantir tried to bridge the gap.
By 2010 startups were again starting to attract people away from traditional "prestige" careers like investment banking, private equity, and medicine. This brought more of the standard careerist status seekers and crowded out some of the dreamers and visionaries, but there was generally room for everyone.
By 2015 the generational shift toward increasing numbers of millenials led to a blurring of the distinction between careerists and dreamers in favor of a more pragmatic form of work identity centered around work/life balance. The pandemic and some long overdue social movements accelerated this further.
But the downside of the millennial "integration" of work+life is the increased appreciation of stability and harmony. This pushes organizations toward monoculture and sometimes (sadly) toward censorship and the elevation of conformity, albeit a variety of conformity that allows for a fair bit of individual aesthetic expression (fashion, pronouns, etc.)
In that sense, HN is simply following the trend, and may in fact have helped lead the charge. Mods want HN to embody the ideals of being predictable, respectable, authoritative, as well as supportive and empathetic. The idea adopted by the mods is that when you remove conspiracy theories, flame wars, and overtly political topics, you achieve those ideals.