You read that right, every time there is a major Bitcoin theft, and no money is recovered, it increases my assurance that this currency is secure.
There've been dozens of million dollar plus thefts, and most recently one rumored to be over 100 million. But here's the good part: none of this has ever been recovered. What that means is that the underlying security of the crypto currency itself must be secure.
Imagine a scenario in the real world, in which dollar thefts of this magnitude were reported. At least some of the money would be recovered. The fact that none of this has been recovered means that the currency is operating as it's designed - as an anonymous, untraceable, currency without central authority.