I think the negative sentiment is largely because of how much the bitcoin evangelists promise. There's a lot of hype and lofty goals tossed around but cryptocurrencies have been around for nearly a decade (If I remember bitcoin started early 2009) and they mostly seem to be used for fraud and speculation now. I'm not saying that the technology is fundamentally useless but the mismatch between delivery and retoric has made me sour on it.

A good more concrete example of this is the DAO from Ethereum. A lot of verbage was wasted beforehand saying how it was going change everything about corporations and investment but as far as I can tell little has changed.

You mean mostly media talks about fraudulent use cases. Or otherwise, how do you know mostly they are used for fraud?

The reason I think it's mostly speculation and fraud is that the only people I know who have crypto currency in real life have it as a speculative investment and that combined with the fact that it doesn't work well as a payment processor (historically it's been slow and expensive and even mainstream companies that used to take it seem to have often discontinued support). I actually don't think they are mostly fraud, I think they are mostly speculation and fraud is just the outcome ofof a speculative market with little regulation. I would be happy to hear about more use cases but most I've heard about have either been small toy use cases or "in the works".

Fraud, speculation, and drug trade. Don't forget about the drugs.

There's ransomware as well.

I think this to. They probably have known about bitcoin since $1 and are trying to convince themselves and the world they were right not to buy.