Interesting. It seems passive voice can be used that way. I don't see any reason to complain unless the usage is strained, though (including, possibly, through the destruction of diversity in sentence structure - a crime that insistence on the active can also commit).
As to your last point, I am not proving witty enough to abide by your request in an amusing manner, so I will simply address your question: it is completely possible to avoid assigning blame with the active. A classic example would be, "They say...". Or compare the active "Someone made a mistake" with the passive "Mistakes were made by Steve."