having OS security patches doesn't mean you can be hacked while firewalled. Mostly these vulnerabilities happen under a very specific scenario, mostly requiring you to visit a malicious website or use a specific application/setting.
Yes, and many hackers have a tool bag of exploits they can execute at their disposal when one fails.
How do you hack 51 delegate's private computer without knowing their IP address, even assuming their computer all have vulnerabilities?
Their are many ways to hack the delegates without knowing any IP addresses: phishing attacks , creating malicious sites or landing pages that exploit 0 day vulnerabilities in java/javascript/flash/pdf/ect..., finding a flaw within bitshares itself, and how about starting by targeting these people:
http://bitshares.org/community/team/All one has to do is compromise one of them and the rest are easily compromised afterwards.
These again, requires the person to actually click something, how do you get them to click on something is your first obstacles. Hacking discus fish or ghash.io doesn't require the site admin to click anything, a newly discovered PHP/Apache/Mysql vulnerability may cause both of them to be hacked at the same time, since they already broadcast their IP and offers a route of entry.
Also the delegate's web browsing device is probably not even the same as their node device, which means all your phishing efforts might be useless.
I don't see how compromising one of bitshares developer's computer does anything. Also, again you'd need to find their IP address first or get them to click on something malicious you own (which I don't think you will be very successful at in a techie community).