"Many websites, especially government ones and those like the FAS, are reviewing their content in light of security concerns. I didn't see anything on Kim's website that seemed wrong."

Either did Kim. But apparently some jerk with handle of "Woohoo", did see something wrong. And instead of helping Kim by alerting him to this problem, the guy apparently used this info to get Kim fired.

"Over reactions will be probable for some time to come, such as NASA keeping the next Shuttle launch time secret until 24 hours before launch. As Raoul pointed out, it wouldn't be all that difficult to calculate the probable launch time given the tightness of the window for ISS missions."

I doubt it had to do with Shuttle schedule. This AFAIK was concerning data that USA considered (or at least claimed was) proprietary.
If I had to guess, I would say it had to do with NASA's potential plan of privatizing the Shuttle (selling them). In this situation USA would be a bidder- in competition with other bidder. Or USA might be "given" a orbitor and info available to NASA, might affect "the pricing".