He argues it's difficult to attack it like that because one would drive up the price too much, thus admitting an attack is possible, albeit difficult... but possible nonetheless... This would be a major concern to me as an investor...
Looks like also that aspect of the FUD has just been obsoleted:
Basically, something called masternode input age based quorum layering. Quorums are created using the age of the masternodes, 25% of the quorums are more than 1.5 years old, the next 25% is more than 1 year old, the next 25% is more than 6 months old, then the final 25% is any masternode that is newer than that. It guarantees, you can't control a quorum by just buying coins from an exchange to make new masternodes, there will always be masternodes that are really, really old.