He said young people are generally more progressive, issue by issue, regardless of their definition of conservative, liberal, democrat, gop, or maga. They want affordable healthcare, better education (including k-12), better infrastructure, stable climate, are pro-choice, don't care about gayness.
But they often aren't paying attention to policy, rather "strong leader" vs "not strong" leader and who is a "fighter". Trump does seem like a fighter, he's good at portraying that. He called Trump an anti-hero: someone he isn't evil, does the right thing but not always for the right reasons. Lots of these people were still teens when Trump was a pres, aren't plugged into policy and "news", rather gaming forum echo machines.
But Kamala comes across as a fighter they can relate too, and that's simply what they want. Kamala is easily winning the "strong" leader competition vs 81 yr old Biden and 78 yr old Trump in their eyes, it only helps that they're progressive leaning aligns with her views.