I think this is enough about network security, it has become irrelevant to the discussion at hand. I believe it's far easier to hack discus fish and ghash.io's web server, than to get 51 delegates to click on your malicious link and somehow you obtain their private node device access thru this link. You may believe differently, that's fine. Again, pools being hacked has happened many times in reality. 51 Bitshare delegates being hacked simultaneously has not happened. I will leave the discussion at this fact.
They don't need to be hacked simultaneously. Once one of them is compromised it is easy to compromise the other half of delegates. Very few people change their passwords often or use unique passwords for everything. Most peoples security is laughable. Even many computer geeks have flawed security behaviors as good security is tedious and time consuming.
It is likely that some of them are already partially or completely compromised as we speak. Yes, lets move on because I also agree with you that Bitcoin is vulnerable as well.
I don't see how hacking one delegate can lead to all other delegate being hacked, since I am actually one of Bitshares 101 delegates, and I have no information regarding other delegates, they are all anonymous to me.