Polemic
Etymology
From Greek "polemikos," "warlike" or "hostile," from "polemos," "war." The metaphor is exact: a polemic treats a disagreement as combat, marshaling arguments as weapons aimed at a target. The word carries no pretense of balance, and skilled readers take a polemic as one committed side of a case, not the whole of it.
noun · /puh-LEM-ik/
A strongly worded attack on or defense of a specific opinion, person, or position.
What it names
The argument written to demolish rather than to weigh — useful to recognize so you can read it for its best points without mistaking its heat for fairness.
Example
Her essay was less an analysis than a polemic, and it electrified everyone who already agreed with her.
Related idea
A polemic attacks a position; a diatribe is often just an outpouring of anger, with less of the polemic’s structured intent to persuade.