They're not talking about musically, though. Bow Wow was a bigger star than almost everyone at one point. Dude was in movies, and had teenage girls falling out...posters on their walls, lines for blocks in-stores. Parents may have bought 1-2 tickets for who they wanted to see, but had to be 3-4 tickets for Bow Wow. You couldn't turn on the TV and not see Bow Wow, black movies had at least a cameo from him.
You can't even dismiss his fans, saying "well it was just kids". Most superstars were for the kids. The Beatles were huge amongst teenagers initially, but their parents HATED them. New Edition were for the kids/teenagers, but had a better transition into adulthood. Now, if you want to talk about being a respectable rapper into adulthood, no, that never happened.