No. You're wrong.Wrong again ! Mt. Gox was not the biggest exchange anymore.
And no it did not have the highest security because it was ran by incompetent people who were in over their heads and were too stubborn to get outside help.
There are now plenty of legitimate exchanges with the highest possible grades of data security backed by some of the biggest venture capitalist in the world. This is called infrastructure growth, Mt.Gox was part of the very infancy of Bitcoin and now the network is getting of it because of its rotten ways only to leave place to more competent and legitimate replacement
The Bitcoin blockchain as yet to be compromised and that's all that matter.
By the way, credit card companies and finance industry gets hacked daily b
Mt. Gox was the largest exchange at the time. Three different news sources.
Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy protection in Japan on Friday,
http://finance.yahoo.com/news/mt-gox-files-bankruptcy-protection-094811743.html
...Once the world's biggest bitcoin exchange, Mt. Gox on Friday filed for bankruptcy protection, saying it may have lost nearly half a billion dollars worth of the virtual coins due to hacking into its faulty computer system...
http://www.reuters.com/article/2014/02/28/us-bitcoin-mtgox-insight-idUSBREA1R06C20140228
...Mt. Gox, once the world’s largest exchange for the virtual currency, set up the phone line after filing for bankruptcy in Tokyo last week with about $480 million in Bitcoins missing...
http://www.bloomberg.com/news/2014-...es-bitcoin-customers-lost-in-translation.html
Credit card companies offer consumer protection from hackers. bitcoin exchanges don't.