In a simple demonstration, a hapless team discovers the truth. "Your server is vulnerable. It's already been cracked. Oh, and by the way, it's already distributing malware for a botnet."
Attitude of management in many organizations is one of the biggest barriers to improved security on the internet. People simply don't want to believe that their systems are vulnerable. Denial is pervasive, and affects organizations from the biggest of the Fortune 500 or Federal government agencies, down to modestly sized companies, local governments, and non-profit corporations.
The attitude of the unnamed client described at the "Following the White Rabbit" blog (link above) is all too common. I suspect that an underlying cause is that people want to believe several things that worked pretty well from an evolutionary perspective, but don't work very well on the internet. When everybody around is a bunch of cave dwellers, consumed entirely with finding food, the marginal difference between the capabilities of "our team" and "the other guys" might be pretty modest, or easy to assess (e.g. "there's five of us, and ten of them... run away!") In fact, even considering the industrialized history of the world, we don't have much experience with the type of scalability that a virtual, software driven environment can provide to an attacker.
Consequently, when faced with a vague potential threat from "the internet", people tend to default to reptillian brain denial.
"These vulnerabilities and exploits look complicated. It's not very likely that anybody could actually exploit them."
They might look complicated to you, a manager, or even a programmer (depending on your particular skill set, which typically won't include "cracking").
They look like a modest engineering or programming exercise, to the people who routinely crack computers for a living. There are toolkits and sample code and it isn't very difficult to build a test bench and try permutations over and over until the crack works.
"Our team isn't that stupid. We wouldn't build and deploy a system that can be easily hacked."
Your site doesn't need to be easily crackable, merely crackable. Some exploits require knowledge of assembly language, SQL, C, C++, and some other specific combination of arcane skills with Internet Explorer, Microsoft Windows, Apache, SQL Server, MySQL, and so forth.
Once somebody with the proper combination of skills has developed the exploit, and shared it with the world, your site could be cracked by somebody with little more programming proficiency than a typical user of IRC (Internet Relay Chat), perhaps someone who needed only drag-and-drop proficiency with a mouse.
"Nobody is that interested in hacking us."
You might be boring, yes. You might have no secrets. But you do have something interesting to them: a computer with a full time internet connection running a web server, and people who visit your web site (sometimes they just want to use your site to spread their botnet to your customers). Furthermore, the bad guys don't know that you don't have any secrets, until they've finished perusing your hard drives and data bases.
Finally, there's the typical denial offered by individual people, when pondering the vulnerability of their own workstation:
"I don't surf to bad web sites, so I won't get a virus (trojan, rootkit, botnet, worm or other malware) on my computer!"
You don't need to point a web browser to a "bad" web site to be victimized by a browser-crawlback. The malware that gets onto your computer may also start poking around your company's internal network, and find ways to exploit or infect systems that don't "surf to a bad web site" or any other web site, at all.
The moral of this story is that we cannot afford to live in a state of denial about the importance of application, network and computer systems security. Enterprises, large and small, need to take the security of their web sites, applications, and internal systems more seriously. The bad guys are kicking your butts. They're stealing your data, and you don't even know it. They're using your systems to spread botnets to your customers.