Bitcoin is radical. Anytime you have something that is radical people will mock it, attack it, and misunderstand it. You aren't going to reach everyone so those who are in "attack mode" are likely best left to stew in their own venom. You aren't going to convince them. There were a half dozen logical fallacies in those quotes but it wouldn't matter if you pointed them out to the authors.
That being said I think the way Bitcoin has been (and mostly still is) introduced is counter productive. How I learned about bitcoin is "Hey you can use your computer to mine digital coins and some people will pay real cash for it". I mean it comes off as inplausible, a pyramid scheme, and some kind of get rich quick scam.
A better way to explain Bitcoin is.
There is this currency which is anonymous, can't be counterfitted, and can't be charged back. The best part is the currency is peer2peer so it is outside the control of central banks and their agendas and the monopolies of VISA/Paypal.
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talk about how it works
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talk about exchanges
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talk about advantages to merchants
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"But wait how does the network prevent fraud?"
Good question. Individuals working together chain transactions into blocks creating an irreversable record of transactions and prevent counterfitting and fraud.
"But why would they do that?"
They are compensated for their time, equiment, and electricity. Eventually the network will be large enough that they can be compensated by a small fee on transactions (much smaller than CC/Paypal) but since network is still small they are given an agreed upon "subsidy" by the protocol.
That sounds more plausible, more believable. I also hate a love/hate relationship with the term "mining". We arne't mining anything. This isn't a video game where you get prizes just for playing. We are hashing the network, providing security, and being compensated for that activity.
The good news is things like OccupyWallstreet accepting Bitcoins add support to the longer useful narrative. Hopefully we see less "Dude you can like minting thousands of dollars by just turning your computer on" and more real world uses for Bitcoin.
What will change people's minds is seeing Bitcoin accepted. If someone trusts the Electronic Freedom Foundation and they accept Bitcoin then that is vote of confidence. If someone like Wikileaks and they prefer donations in Bitcoins then that person may decide to learn more
with an open mind.