I have to say that my response to bad advice depends on where it is, what it is, what it's about, the tone it's delivered in, and the history of the person writing it.

If, for example, I see a minor error in a piece of complex code, in reply to a poorly written request for help, I'll just suggest a correction and nothing more.

On the other hand, if I see something posted that could result in serious data loss, posted in an authoritative manner, without clarification that it will result in data loss (I see this pretty regularly), I'll jump on it a little more harshly. Since that's the kind of thing that can result in losses for companies and job-loss for the DBA affected, I treat it a little more seriously.

When corrected myself (happens more often than I like), I take my error personally, but not the correction. If I posted something that will cause a problem for someone else, that's serious to me, even if it isn't to anyone else. That's certainly not a flaw in the person correcting me.