"People wanted really to see you get mad when Trump started lying about Hunter – and saying things about Hunter. I don't know that you got mad enough," co-host Joy Behar said on Thursday's show.
Behar also asked Biden about Burisma, the company at the center of Republican allegations against Hunter and his work in Ukraine.
"How are you going to handle that?" she asked. "Because it sinks in." Biden responded by appearing to claim that impeachment witnesses defended his conduct.
"The thing that sinks in is that every single person who testified from his administration, under oath, testified I did my job – I did it thoroughly, I did it honorably – there was nothing but leading the rest of the world along the route that we wanted to go," he said.
He added that Trump's attacks were "way, way, way over the top." Co-host Sunny Hostin agreed, saying that Republicans "play dirty."
Biden also defended himself, saying he's never been accused of doing anything indecent.
"The bad news for me is I'm authentic. I say what I mean, I mean what I say, and sometimes I say all that I mean," he said.
"You are authentic," Hostin concurred, before saying that quality would have made him a good witness in Trump's Senate trial.
When she asked why he didn't testify, Biden said he didn't want to help Trump create a distraction. Hostin also asked Biden's wife, Jill, how "hurtful" the attacks on Hunter have been.
Toward the end of Biden's interview, Hostin asked the former vice president about Sen. Lindsey Graham, R-S.C., backing an investigation into his son.
After Biden's relatively tepid response, Hostin said: "I think Lindsey Graham should be ashamed of himself."