I decided to read the rest of the article and found this:
“For one, we know who the soothsayer was and what he really said: he was named Spurinna, and he was from Etruria. That’s important, because Etruscans were known to specialize in divination. Cicero’s letters , Plutarch, and Suetonius all confirm his high status. As notably, Spurinna’s warning to Caesar was more complex — and more accurate — than the type of prophecy most modern skeptics would dismiss. “They have a lot of contacts,” Strauss says, “and they’re people who know what’s going on.” That would have made Spurinna’s prophecy a more frightening bellwether of the anti-Caesar sentiment in Rome. Soothsayers could poll the elites, and the elites did not like Caesar.
On February 15, Spurinna said he found a bad omen: a bull without a heart (it’s unclear if the bull was a genetic abnormality, a shocking sign, or a soothsayer’s poetic license). After that, Spurinna told Caesar to beware for the next 30 days, not just on the Ides of March. It wasn’t a lucky prediction but rather a calculated assessment of Rome’s political climate. The end date of the prophecy wasn’t a coincidence, either — on March 18, Caesar was going to embark on a multiyear military campaign that would take him away from Rome. The assassins had to kill him before he left.”
Thus, there were large numbers of veteran soldiers in and around Rome looking forward to going off to Parthia with Caesar with paydays, looting, etc. If, in fact, Cassius believed this was foolishness, then that would explain why he was not able to win them over.
Divus Julius 81.2: Et immolantem haruspex Spurinna monuit, caveret periculum, quod non ultra Martias Idus proferetur..