The poem’s original title in 1912 was: “on hearing that the students of our new University have joined the ancient order of Hibernians and the agitation against immoral Literature.”

The new university is University College Dublin, (as opposed to old-school Trinity College)

And the Hibernians is an "aggressively Catholic" Irish-American society based in New York.

"Immoral Literature" refers to the controversial Abbey Theatre tour in America that sparked riots. It was stirred up by Irish nationalists and republicans who felt the "playboy play" was "an offence to public morals."

When Yeats got back to Ireland after the tour, he was greeted with students from the newer university (UCD) rioting against his Abbey theatre, again, over the "immoral play."

So the polemical poet smelled irony: an untraditional, newer, younger university, and its youths, (the older universities did not riot), ironically were the parochial ones, who blindly took side with a political party, took up empty slogans of "Pride and Truth" (ostensibly Yeats' drama humiliated Ireland and hurt its pride with its immoral contents), and were easily manipulated into riots, in order to "restrain" middle-aged cultural figures like Yeats and Lady Gregory (Directors at Abbey Theatre.)

The new institution wants to defend "old" values; the young people wants to dictate to middle-aged established figures what they mustn't do.

I should point out Yeats routinely mocked the hypocrisy of the middle-class nationalists, not just in this poem, not just in this collection (The Green Helmet and Other Poems), but repeatedly in his plays as well. And he's not subtle about it, he literally had a director on stage ranting about "this foul age" and spitting on "middle class audiences". He depicts (on stage) "Satan" as a British merchant bringing capitalism to the good but easily manipulated Irish peasants. (Though the Green Helmet is probably the most polemical -- and fascistic -- of his whole corpus of works.)