I understand the reason behind - but it is still contradictory. People expect IT vendors to quickly inform them about security issues. And people then blame them for the security issues. OK, if there are security issues which affect someone, he has some reason to blame the company responsible for these. Nevertheless, some more fairness would help in achieving even more openness. If you have to admit a security issue and you fix it, then this is obviously better than just trying to hide what has happened.
Let's take some examples. Microsoft has been bashed for years for not doing even to secure its products. They have built a sophisticated system for patching and informing the public. They are very open regarding security weaknesses. But they are still blamed for being insecure. Apple is much more reluctant in its openness regarding security issues. But they aren't blamed as much as Microsoft. Fair or unfair? I personally prefer the Microsoft approach - Microsoft has been amongst the first to provide a patch for the DigiNotar case. It took Apple much longer.
The DigiNotar case is my second example. Today the news of bankruptcy spread the news, after DigiNotar had to admit that their root CA (Certificate Authority) became hacked. The bad thing is that it looks like DigiNotar knew about that way before. They didn't inform the public. Good or bad? I opt for bad - they severly increased the security risks in the entire Internet.
RSA Security is another example. They informed the public about the hack of the RSA SecurID seeds. They informed their customers. And they got blamed. I believe that the RSA approach is far better than the DigiNotar approach. Customers were informed and thus able to react. RSA spend a lot of money for helping customers to address their issues.
We can blame all, Microsoft, Apple, DigiNotar, RSA, and all the others not mentioned for security bugs. I remember a professor of informatics calculating back in the 1960's that starting with a defined (relatively low) number of lines of code there is no chance to avoid bugs. Thus, security bugs in code and security weaknesses in IT environments are somewhat "natural". And, by the way, it's always a question of how much you invest in attacks to succeed. There is no absolute security. RSA did a lot to secure the seeds, knowing that they are the biggest risk (and every RSA SecurID customer could and should have known of that "single point of failure"). DigiNotar, from what I've heard, didn't do as much. Microsoft has invested massively in improving security, but still is on a long-year journey for better code and so on.
At least, it is a difficult balance. Openness can't be an excuse for security issues. But openness is better than fuzzing around or hiding security issues. Openness allows the customers to evaluate their risks and to act. And risks are better than uncertainty, which is the result of not being open around security issues. You can avoid risks - but it's hard to deal with uncertainty.