> the overall community didn't thought the system would survive the eventual switch to proof of stake if 15% of all ether was in the hands of malicious actor

The author of Casper, Vlad Zamfir, clearly stated on numerous occasions on Reddit that there was no risk to PoS b/c of the hack.

> There was also the moral matter that something could indeed be done to actually return the stolen money to their original owners

That's a really nice way of phrasing "we have a moral right to help gamblers recoup their losses."