HN changed my life. Seriously. I started using this site fairly young, and it shaped my view of the world and who I am as a person more than almost anything.
Because of HN comments, I fixed some serious health issues (search your symptoms on HN, write down all the wacky advice, and do everything that's safe!), I tried MDMA (which is magical), I made tons of money, I kept my mind sharp, I traveled to interesting places, I found other groups that led to lifelong friendships...
HN also recommended me every single one of my favorite books (mostly old fiction), a good portion of my wardrobe (Darn Tough socks, various denim etc), my laptops, my audio setup, and my financial setup. Heck, even my underwear was a recommendation from HN - if you haven't, try merino wool underwear, it feels like your ass is being caressed by God.
You specifically mentioned romance and sex, so I'll touch on that aspect. The most valuable advice HN gave me on this subject was that attractiveness is not set in stone. Take the most attractive actors and take away their personal grooming, their fashionable well-fitting clothes, their physical condition, their clean skin, their diet, confidence, career, money and relationships and you'll have someone that would fail to catch your eye at McDonalds. (Seriously - look up the ones who went off the rails.) All of the above are things that anyone can improve. Fix a number of those things, find attractive women and talk to them like they're human and not a sex object - and I can guarantee you sexual and romantic success. I was an unattractive nerd who was laughed down by girls and even fixing a minority of the items on the list above was enough that (pre-Covid) I never had a problem finding beautiful, intelligent, interesting women for serious relationships, casual dating or sex. Everyone I know who's done the same has had similar results. You won't meet a partner on HN (or Reddit, or Facebook, or anywhere) - despite their colossal userbases, there are only a few stories of people who met their partner on those sites. The best dating site was pre-2017 OKCupid, but that is dead and gone now. Real life is your best shot - otherwise try Tinder, or modern OKCupid.
Another reason this place is beautiful is because of the small community feel, despite being a relatively large website. Many people know each other IRL, many get to know the names they butt heads with, and when one of the many famous users drops in there's often an intelligent and interesting discussion. For that reason I'm very hesitant to see it grow. In that regard, I'm thankful for the 90s design, large amount of boring programming things (I can code, but many of the programming posts are drier than hell), and even to a degree the new-user-unfriendly atmosphere - they all slow growth. Serious growth would be fatal to a place like this.
HN isn't great for everything, though. Music is one huge blind spot. Another thing is that the HN discussion style doesn't carry on over into the real world. HN will love your massive, detailed comment and it will ask for more, but in the real world even people who love and care about you have a finite, human attention span. On HN, if you keep your argument short and simple people will poke holes in it, but in the real world nobody expects your arguments to be watertight and bulletproof (and you better not expect that of others' arguments!)
Spend too much time in HN, and it rubs off on you: the skeptical attitude, the long-windedness, the cultural and political views and most importantly the feeling of superiority. Even stupid people aren't stupid - they'll sense your feelings of superiority eventually. It's easy to fall into this because HN values the optimal, and it values comments correcting someone's non-optimal ways. For example, with retirement accounts, even a relatively minor mistake (an account or ETF with high fees, wrong type of contributions, etc etc) can compound into missed tens of thousands of dollars. Logic would dictate that you should tell as many people about this as possible! Practical experience, however, tells me that no matter how you explain things, _most_ people will just feel bad about themselves for their mistake (even if they don't show it) and oftentimes won't even correct it. If you really can't help yourself, you can casually mention the topic as gently and briefly as possible - "oh cool, I did xyz for a while too, then I heard that abc might be better, you should look it up sometime." Alternatively, don't make it into a comparison - just (briefly!) mention your positive experience and let that stand alone.
If you understand that last paragraph, you will finally understand why so many people truly hate vegans, or nerds, or the modern left... or HN users. People like people that are like them, and if you feel like you're not like them, you won't be liked. If you try to convert them to your ideology, or insist it's the only option, you will be hated. You can narrow down your life goals, your identity and your politics to a tiny segment of the population, or you can look to our common aspects and realize that we're all human, just trying to live our short lives on this tiny blue dot of a planet.