Well, hacking bitcoin blockchain is a bit hard. But hacking exchanges is so easy..
For greed: "to the moon" and "hodl" slogans are, by some point of view, a sign of greed. Volatility and "OMG huge profits" are the reign of traditional system, that now is heavy working on bitcoin market.
Think to this: the same people that consider bitcoin as a sort of bank-killer, where the same that celebrated when banks supported CME future. Then, when moon didn't arrive, they started complain because banks supported CME futures. It is a bit crazy, and definitely a bit insane...
I think so many people didn't see the cliff there. By the time it happened I knew it may not be the most stable option, especially considering they didn't even have to interact with BTC to bet against the market. It's scary, and I had a chill down my spine with the famous "We'll tame bitcoin" quote. Institutional money can be good, but it can't be the churn and burn speculators that make profit at all cost. They sink all ships just like the economy in 2008.