ET spoke to the 64-year-old comedian on Monday about a new season of his show,Comedians in Cars Getting Coffee, coming to Netflix, and also got his candid thoughts on the controversy surrounding Barr's remarks.
"I didn't see why it was necessary to fire her," Seinfeld said. "Why would you murder someone who's committing suicide?"
"But I never saw someone ruin their entire career with one button push," he added. "That was fresh."
Seinfeld also said he thought another female comedian should get a chance to play Barr's part.
"I think they should get another Roseanne," he advised. "They brought Dan Conner back, he was dead and they brought him back. So, why can't we get another Roseanne? There's other funny women that could do that part. You need to get the comic in there. I hate to see a comic lose a job."
As for Comedians in Cars Getting Coffee, Seinfeld dished about hanging out with lots of A-list guests this season, including Ellen DeGeneres.
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"It was fun," he said of his candid chat with the daytime talk show host. "And then we had an interesting conversation about penises, but I'll let you watch that. But it's clean, believe it or not. ... Yeah, we started discussing, 'If you're a lesbian, what do you think of the penis? Is it something you hate? Or are you OK with it?' She said she was OK with it. She just says she doesn't really feel one way or the other about it, and I said, 'That's the way I feel.'"
Seinfeld also explained why this show is important to him. "I felt like there's another world to being a comedian that the public never sees and it's not on a talk show and it's not in some of these other interview shows that are on TV," he noted of the series, which features him taking a drive with a famous comedian and sitting down over a cup of coffee. "I thought I gotta get them out of the package, out of the wrapper and just go to a coffee shop and hang out and then you see the real person."
The new season of Comedians in Cars Getting Coffee starts streaming July 6 on Netflix.