You need to understand the context that some of his fans are young.Ordinary people who are not celebrities, don't have the same need to be mindful of their fans when they speak. So, if an ordinary person made the exact same statement, it would carry a different meaning.
He is merely making an objective point that, even if such people exist, the law, parental consent, and the mutual consent of the people involved are important.
He never once said that dating a 15-year-old is legal.
As a Japanese speaker, I understand him to be saying no.
Because some of his fans are young, he is simply avoiding being too direct in his wording.
At some point, he shifts the discussion away from himself and starts talking about hypothetical situations involving other people.