In my experience if you attempt to push back and ask how exactly they propose to fix these problems they'll just resort to enumerating the failings of our current system (the 2008 crisis, wealth inequality, tax evasion by the wealthiest etc...) which is all fair, but how does cryptocurrency fix this? I'd argue that so far it's mostly demonstrated that it shares all these issues, only even more pronounced.
The pyramid scheme at the core of cryptocurrency poisons the well, that's the original issue with this entire thing. You can't have a good faith discussion when one side expects that they're going to be billionaires if things go their way. I acknowledge that there's definitely toxicity coming from us cryptoskeptics, but you have to acknowledge that these days easily 90% of any discussion involving cryptocurrencies is going to use shallow catchphrases pushed by people who don't understand the technology, don't understand basic economic principles and are just hoping that their $1000 in ShitCumShibaCoin is going to make them millionaires.
On top of that the cryptocurrency side has over a decade of unfulfilled promises to account for. As far as I'm concerned we've exhausted the discussion years ago. Any debate surrounding cryptocurrencies on HN from 2017 is equally as relevant today, there's no need to keep repeating the same arguments over and over again from both sides. So today I mostly dismiss anything cryptocurrency-related as a scam and move on. It works well, too.