Final answer:
Marullus is frustrated with the Roman people for their fickle loyalties, as they quickly shift their support from Pompey, once a celebrated military leader and part of the powerful First Triumvirate, to Caesar, whose rising power worries the senators.
Step-by-step explanation:
When Marullus compares Caesar to his predecessor Pompey, he is frustrated with the people of Rome because they seem to be fickle in their loyalties.
The citizens who once supported and celebrated Pompey are now just as enthusiastically celebrating Caesar, despite Caesar's direct opposition to what Pompey stood for.
In history, both Pompey and Caesar were viewed as strong military leaders, but their portrayals by contemporaries like Plutarch and Suetonius highlight their political and personal vices, leading to the complexity of public sentiment towards them.
The frustration expressed by Marullus likely stems from the Roman people’s quick shift in allegiance from Pompey to Caesar, disregarding Pompey's past services and status in Rome, and instead embracing Caesar, whose rising power was a cause of concern among the senators.
Pompey was once a celebrated Roman general and, together with Caesar and Crassus, part of the First Triumvirate wielding significant political power. However, his relationship with Caesar became strained, leading to civil war.
Furthermore, Pompey's political marriage to Julia, Caesar's daughter, was initially tactical but became genuine, which may have also contributed to public perception.
Despite Pompey's loyalty and military achievements, the fickleness of the Roman people is apparent as they readily shift their support to Caesar.