Active voice, Passive voice

I found this interesting piece of information in a post on GmatClub Verbal Forum

The point is that in most cases we should avoid passive voice, meaning that there might be some constructions in which we would have nothing to do but use passive voice. I assume those cases are rare. But in general active voice is preferred. The same applies to being. Some sources claim that constructions employing being are as a rule incorrect, but there are exceptions.