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Following Thursday night's Democratic debate, Julián Castro stressed that he wasn't trying to insult former Vice President Joe Biden when he asked why he can't remember anything.

ABC News reporters asked Castro if he regretted an exchange he had with Biden early in the debate — while discussing health care, Castro was adamant that Biden had said one thing about his plan before flip-flopping and giving a different answer. "Are you forgetting what you said two minutes ago?" Castro asked Biden, which elicited some boos from the crowd.

Castro said no, he didn't feel bad about this, because "it's an argument about health care policy, this is important. We're talking about a policy that is going to impact every single person in this country."

Several reporters on Twitter, as well as ABC News' Jon Karl, said Castro was wrong to accuse Biden of changing his answer, with Karl saying Castro "mischaracterized" Biden's words. Castro insisted that he read the transcript, and was correct with his criticism. The 44-year-old also denied that his remark on Biden's memory was meant to call attention to the fact that he is 76 years old. "I wasn't taking a shot at his age," Castro said, adding, "It's not an attack on Vice President Biden, something about the personalities. It's about the health care policy." Catherine Garcia