If a good countermeasure is factually impossible (i.e. there's a law of nature denying it), keeping things secret only delay the inevitable. I'd rather struggle against inevitable death fully knowing this very fact (and fail), than live blissfully ignorant.
Absurdism aside, we currently don't know whether a countermeasure exist. So give ourselves a chance. The genie of biotechnology has been out of the bottle at least a decade go, so why let more people informed about it? I think the late physician Lewis Thomas summed it up in an essay on the ethics of biomed research, which I cannot bring up exactly now. But I remember his point: censoring scientific research due to the fear of uncomfortable truths only limit our own choices in the face of change which is likely to the detriment of our survival as a race.
To answer your second point: the individual researcher is not likely to go rampage but governments are. That's why citizens must know the possible ways the government could perform evil so that we can better constrain the beast. That's why we need the information. As for the black swan bad guy argument, I just point out that the good guys are just as many as the bad guys, and as competent, if not better (and I assume much better). The bad guys can walk the earth unhindered only if their arsenal are not understood by the good guys.
Look, we slashdotters are having great arguments in this thread and we began thinking about securing our better future even if we're arguing. We don't usually spend time thinking this way. And this is precisely because there *is* a story getting published rather than kept secret. I think it works this way for us. Publish and enable wisdom.