Every crypto thread has lots of crypto lovers and lots of crypto haters. If you only see the hater then you are probably a lover.

I'm thinking the answer to such topics would be 'HN has large numbers of poster who are either smart and ethical, or smart, unethical, and not convinced the scam of crypto is safe to work on people for your personal gain'.

With China turning against bitcoin (regardless of their motivation), the latter category has even more reason to think cryptocurrency is a lousy way to fleece people for your personal gain. You don't have to be ethical to be against crypto, you can be a scammer yourself and simply be unsatisfied with the quality of the exploit being proposed.

"There is no future in this" is a fine reason to be against a thing even if you have no ethical qualms about exploiting people's foolishness. You have to be able to build a plausible case for why somebody ought to buy into it, and that just got observably harder.