Large or not, it is just a website which can be banned or hacked, it is still very new, and it is just a centralized clone of bitshares.
MtGox, Bitstamp, and Bitfinex all had very long running track records, yet all were hacked.
They have grown quickly due to their referral program, but they still require all data, which means IRS (or equivalent) reporting.
You are correct. No platform is above being hacked. I just suggest that everyone have that extra security with 2FA. I also strongly suggest not keeping your Crypto on an exchange for a long period of time.