I am trying to understanding why the be-verb is needed when the object of preposition becomes the subject when written in the passive voice, while when the direct object of the sentence becomes the subject in the passive voice, the same rule doesn't apply.
I am assuming that "to get rid of" means "to rid of" in the passive voice, thus safely assuming, grammatically, it can be replaced by "to be rid of."
Example Sentence: The governor rid the state of crimes.
When the direct object of the sentence becomes the subject:
The state got rid of crimes (by the governor).
When the object of preposition becomes the subject:
Crimes were gotten rid of (in the state by the governor).
Is there a rule that constitutes this case? Or is this something unique to the verb "to rid"? Or is my view of "to get rid of" as the passive voice wrong?