Those sentences sound reasonable to you because they are correctly-constructed passive voice sentences. There is nothing “incorrect” about passive voice—it’s a normal feature of English (and many other languages)—but style guides often recommend against it because a stronger and clearer sentence might be available in the active voice. However, when you want to de-emphasize the “doer” of the verb, or when you want to emphasize the thing with/to which the verb was done, the passive voice might just be the best option.
Excellent response. I agree completely. I taught advanced legal writing in law school for years, and a point I made often is that the use of the passive voice can be very effective for purposes of emphasizing one thing, or de-emphasizing another. I often used a famous sentence from a legal opinion written by master stylist and jurist Benjamin Cardozo describing a murder: The pistol came from the pocket., and from the pistol a single shot, which did its deadly work. Notice how the shooter was made to disappear? In any case, as I always told my students: Using the passive voice is fine, just make sure you use it on purpose and for a good reason. Sloppy writers lapse unknowingly into the passive voice, which is why teachers tend to nudge toward use of the active voice. But, as other comments have noted, there is nothing incorrect about the passive voice.