The dreaded passive voice…

So.  I just got called out in class today for using the passive voice in a blog post.

I just looked back at the blog post.  I’m frequently guilty of indulging my desire to fall into the passive voice, so I wasn’t surprised when the professor said that I had done so.  However: the specific example in the post in question brings up an issue that I’ve often had when people say to avoid the passive voice: aren’t there some times when it is necessary? 

I looked at the sentence, and it’s pretty much what I wanted to say:  "In January of 1917, a pamphlet was published…" The thing had about 15 signators, if memory and my quickly-scrawled notes serve me right.  I can’t rightly say who wrote it– surely the entire committee did not.  In my experience with writing by committee, one or several people write something, and the rest sign off.  Or offer revisions.  But I doubt all 15 people sat in a room, passing around the pen.  Moreover, again, I’m working on memory and notes here, but I don’t recall a publisher being listed anywhere. 

How could I put this into the active voice?  I can’t say, "Someone wrote a pamphlet," or "Some dude published this broadside," can I?  That sounds worse than the passive voice, to my ear.  I guess I could say, "a pamphlet appeared," but that sounds like some sort of mystical process.

I know that "The passive voice should be avoided," (har, har…) but it seems as if sometimes it’s the right stylistic decision.  How do you not resort to it when you’re faced with holes in the historical record?  It seems that sometimes there are documents that are too important to be thrown out just to avoid an "incorrect" voice…  The English Language has a passive voice for a reason– it avoids direct agency, which can be significant, even important, to do at times.  Sometimes it’s best to agree that "mistakes were made."

Can’t it be acceptable in Historical writing to utilize this voice’s capacity to elide certain gaps in information?