Earlier quoted context omitted.
> there is no passive voice in the sentence you quoted There is no finite passive verb, but "acknowledged" is a passive form in the sentence in question. It's just a participle rather than a finite verb.
okay, you're right, i wasn't paying attention. shame on me. Still, I think it is a stretch to point to the use of this passive participle as the reason why this sentence works or doesn't work.
I find this attitude troubling in combination with the argument made all over this thread that you can tell the people who say not to use passives are full of it because they can't even identify a passive when they're looking at one. (And you're at least flirting with that argument in your comment above.)
It's completely true that the advice not to use passives is spurious. That advice is an American cultural phenomenon in the same way that advice not to sleep in a room with a running electric fan is a Korean cultural phenomenon, and it's just as valid.
But it's kind of difficult to simultaneously make the arguments that (1) You don't know what you're saying; you can't even tell whether a verb is passive or not, and (2) OK, this verb is passive and I didn't notice, but that shouldn't take anything away from my arguments.
I'd prefer to see the case for passive usage made based on the actual purpose the passive serves (letting you rearrange the elements of the sentence, so that the order in which they are presented better suits the overall flow of the discourse) than based on gotchas.