Bitcoin is anonymous in the sense that you don't necessarily need to link your wallet to your real name, it's just not the best choice for privacy since transaction details are public. Besides, mixing services exist.
And don't work. They were revealed to be useless way back when the Magic The Gathering Online Exchange crypto grifters pulled the first high profile scam, and they got hounded through all the "mixers" anyway. Chainalysis has been able to see straight through "crypto mixers" for almost a decade. (Yeah, there are probably way that right now you can't track bitcoin through other crypto currencies and back into bitcoin, maybe... But we are now a long long way from "good advice to an old guy who want to sell macOS utilities anonymously")
Mixers on programmable blockchains like TornadoCash do seem to provide strong anonymity when used correctly. If you have evidence suggesting its cryptography can easily be cracked, feel free to point to that.
If HN was anonymous, then we couldn't see that two posts were made by the same account or not. But HN has pseudonyms with (unlimited?) pseudonyms per person, and Bitcoin is a bit like that, except that it's commonplace to have many pseudonyms (wallet).
HN is also similar to a blockchain in another regard - You can't really delete your account and its content, which really annoys me to be honest. I like to purge online accounts from time to time, but that's not possible with HN.
