Can knowledge ever be a bad thing?

Define bad.

Hamlet says, "There is nothing either good or bad, but thinking makes it so." Bad, like beauty, is in the eye of the beholder.

A scientist may argue that an increase in knowledge can never be bad, in and of itself, though like the atomic bomb, it may be bad NEWS, to some.

I have heard people say, "There are certain things we shouldn't know," but I can't remember what those things were at the moment, and I certainly didn't agree with them at the time. There are, of course, plenty of people around who are quick to say there are certain things YOU shouldn't know, that are BAD for you to know. Those people are not nice and should be avoided.

Knowledge cannot be inherently good or bad. It is does not care either way. The mechanisms behind nuclear weapons are no exception, they can be used for any purpose that a sentient being desires to use them for. Even the bombs themselves are not evil, it just may have been used in a questionable manner. The bomb has no intention and I believe that consciousness would be necessary for evil.

Both DGC and nas agree that information and knowledge, on their face, are neutral with respect to any moral charge. Where and how does that moral charge enter the picture? And once it becomes a factor, can it then "bend around" to affect knowledge? Are there situations, for instance, in which we should selectively avoid certain elements of information for moral reasons?

I would say that moral charge enters the picture as soon as you have a picture. Meaning: that by the fact that there is sentience involved, there is necessarily decision making regarding what to do with information. So while the entity itself cannot be good/evil, the fact of its' existence (as knowledge) inherently requires there to be good or evil.

In terms of avoiding information, do you have an example in mind?