Here's how it works:
* Exaggeration: The writer likely amplifies Mr. Dobbin's ignorance and cruelty beyond what's realistically expected of a single teacher. This exaggeration makes the flaws more visible and memorable. Perhaps he's exceptionally biased, uses outdated and harmful teaching methods, or displays a shocking lack of empathy.
* Juxtaposition: The character's actions might be juxtaposed against ideals of education and community spirit, creating an ironic contrast. A kind, progressive teacher in the same town would highlight the stark difference and the absurdity of Dobbin's behavior.
* Social Commentary: The satire isn't just about Mr. Dobbin himself; it's about the systems that might have allowed him to thrive (or at least survive) in his position. It comments on the lack of oversight, the acceptance of traditional prejudices, or the limited opportunities for educational reform within a small town.
* Humor (potentially): While satire doesn't always have to be funny, the exaggeration of Dobbin's flaws could be presented in a comedic way, highlighting the ridiculousness of his actions. This makes the critique more accessible and memorable.
In short, Mr. Dobbin's portrayal acts as a satirical vehicle to criticize the potential ignorance and cruelty of some small-town educational environments, using exaggeration and irony to expose and ultimately condemn these negative aspects. The goal is not simply to show a bad teacher, but to use that teacher as a symbol representing a larger, problematic system.