How does act 1, scene 1 of Julius Caesar show the fickle-mindedness of the crowd

In act 1, scene 1 of Julius Caesar, Flavius and Marullus walk through the streets and discover that many working-class men are not at their shops. They stop some of the men and inquire why they are not working today. A cobbler responds to Marullus that "indeed, sir, we / make holiday to see Caesar and to rejoice in his triumph" (1.1.33–35). Marullus responds:

Wherefore rejoice? What conquest brings he home?What tributaries follow him to RomeTo grace in captive bonds his chariot wheels?You blocks, you stones, you worse than senselessthings!O you hard hearts, you cruel men of Rome,Knew you not Pompey? Many a time and oftHave you climbed up to walls and battlements,To towers and windows, yea, to chimney tops,Your infants in your arms, and there have satThe livelong day, with patient expectation,To see great Pompey pass the streets of Rome.And when you saw his chariot but appear,Have you not made an universal shout,That Tiber trembled underneath her banksTo hear the replication of your soundsMade in her concave shores?And do you now put on your best attire?And do you now cull out a holiday?And do you now strew flowers in his wayThat comes in triumph over Pompey’s blood?Be gone!Run to your houses, fall upon your knees,Pray to the gods to intermit the plagueThat needs must light on this ingratitude (1.1.36–60).


Marullus berates the cobbler, pointing out that in prior years the cobbler, and many like him, was one of the people who cheered on Pompey, the former ruler of Rome.

Now, however, Caesar has taken over. This means the downfall of Pompey, but the crowd still gathers to cheer on Caesar anyway. The same crowds that supported the former ruler have quickly turned to support the new one. Marullus is disgusted at how quickly the public opinion has turned and tries to make the cobbler feel guilty about this fickleness. The fickleness of the masses and their ability to be so easily influenced is one of the ongoing themes of the play.
https://www.folgerdigitaltexts.org/html/JC.html