Blame as a verb assigns responsibility to an agent for a deplorable fact or act. There are two different constructions:
1) with the agent as direct object and the fact or act as object of the preposition for
He blames her for his brother's death.
He blames her for betraying his brother.
2) with the fact or act as direct object and the agent as object of the preposition on
He blames his brother's death on her.
He blames his brother's betrayal on her.
In the passive, you re-cast the active direct object as the subject, so with blame the construction you use is the one in which your subject is the active direct object. In your example, the subject is the deplorable fact melodramatic or banal prose, so you use the on construction.
We blame melodramatic or banal prose on the author. →
Melodramatic or banal prose gets blamed on the author.
The first part of this answer is quoted from my Answer to an earlier question here.