Luntz told "The Ingraham Angle" Monday that the current 2020 Democratic front-runner was wise to avoid the San Francisco event Saturday because he should hold off on expressing contrast until the debates.
"If I were advising him, I would have told him to skip this," the pollster claimed. "The senator - the vice president - does not want to be compared to his opponents until he gets on the debate stage."
Luntz charged Biden's wide lead lends itself to the candidate not wanting to be compared with any competitors.
"His goal is, you don't want to be side-by-side with them. You don't want to be compared to them. You only want to do it when it matters," he claimed. "So, actually, I think it was a good strategy to skip California."
Host Laura Ingraham added some candidates who made speeches at the event appeared to criticize Biden's absence.
There is a debate among presidential candidates who have spoken to you here in this room and those who have chosen for whatever reason not to be in this room," Sen. Bernie Sanders, I-Vt., said.
Other Democratic presidential candidates used the forum as an opportunity to speak about their campaign platform.
On her own turf in California, Sen. Kamala Harris, D-Calif., used the convention to emphasize the fight ahead.
"It’s a fight for who we are as a people," she said. "It’s a fight for the highest ideals or our nation. And Democrats, with this president, it’s a fight for truth itself,” Harris claimed.
Fox News' Vandana Rambaran contributed to this report.