Why does Pope compare Addison with Atticus and Cato?

Pope was engaged in a literary spat with Joseph Addison—eighteenth century man of letters and editor of the hugely influential periodical The Spectator. Pope had been engaged in a major new translation of Homer's Odyssey. At the same time, a rival translation was being produced which was patronized by Addison. Not surprisingly, Addison openly expressed his opinion that it was the better of the two translations. The ever-proud Pope, never slow to take offense, went on the attack, using his biting satirical wit to answer back in "Atticus," which was later worked up into the much longer "Epistle to Dr. Arbuthnot."
Pope uses the poem to settle a number of personal scores. Literary feuds were rife in eighteenth century England, and Pope was personally involved in a fair few of them. In the "Epistle" the relevant lines of the poem compare Addison to Atticus, a correspondent of the great Roman statesman Cicero. Pope uses the comparison as Atticus was someone notoriously reluctant to take sides in any dispute, always hoping to avoid giving offense. It is notable that Addison had not in any way trashed Pope's translation of the Odyssey; he had simply expressed a preference for the rival translation. Yet this was enough to earn him the undying enmity of Pope.
The most caustic reference to Addison in the "Epistle" comes in the following lines:


Dreading even fools, by flatterers besieged,
And so obliging, that he ne'er obliged;


Like Cato, give his little senate laws,
And sit attentive to his own applause



Cato was a great Roman senator and statesmen who gained a reputation as a redoubtable defender of the Roman Republic. He was implacably hostile towards Julius Caesar, seeing him as a dangerous tyrant who wanted to destroy the republic and make himself king. Cato was also the hero of a play written by Addison. Pope accuses Addison of being part of a fawning literary cabal, a group of men who regularly meet up and lavish sycophantic praise on Addison, their Cato. Just as Cato the statesman gave laws to his loyal followers and basked in their generous applause, so Addison hands down his literary opinions to his crawling acolytes, opinions they treat as gospel.
https://www.poetryfoundation.org/poems/44895/epistle-to-dr-arbuthnot