It usually seems far more nuanced to me. People seem somewhat skeptical on some finer points of cryptocurrencies, blockchains and distributed ledger ideas.
But then they see supporters trumpeting 'this is good for Xcoin' on every piece of news, good or bad, and can't help but get a snake-oil-salesman-y feeling from that. Everything in life has many ways in which it can or does suck, and you won't want to trust people who handwaive away or dismiss the sucky parts.
So... partially reasonable technical and idea concerns, and partially a PR problem that anything with a particularly large and vocal fanbase will have.
Many (most?) of the conversations I see on here around crypto are copiously littered with straight FUD. Very little arguing on the actual nuances and intricacies of crypto. Seemingly low understanding / imagination of the possibilities allowed by the underlying concepts. Histrionics about power consumption in every thread.
Disclosure: I liquidated my crypto positions last year, and currently hold $0 worth of cryptocurrency.
So when I see someone advocating for Bitcoin specifically they come off as transparently self-serving and having no real interest in the technology. I see a lot of parallels to projects refusing to migrate off of Python 2, except in this case Bitcoin enthusiasts are compelled to actively evangelize the inferior technology instead of just sticking to it as the rest of the technology space moves along.
It doesn’t replace mail, it isn’t used mainstream for anything but illegal activity and casino speculation, and I’m not sure what productivity boost we are talking about here.
At some point you don’t get to make the internet or the “Henry Ford said they’d ask for a faster horse” comparison.
At some point you have to deliver the goods. Has coinbase made a shitload of money, sure. Has blockchain done any of the things its prophets have promised? Nope.