There's a big difference between healthy wants and addiction. The latter involves compulsion and craving. The clearest sign anyone is addicted to something is that they use something precisely when even they don't want to.

I'd even say it's orthogonal to the content and what someone wants to see. You can design an app full of crap that's addictive purely because of its reward mechanisms, and on the other hand you can design something that discourages addiction while having high quality content, it's not optimizing for the same thing. People get addicted to mechanisms, not to content, the same way you can enjoy a nice scotch but the addict goes for the five dollar handle of vodka. The latter doesn't want the vodka, he wants the alcohol.

Addiction in many ways erodes genuine higher-order wants and only leaves stimulation. I'd not be surprised if people who watch 8 hours of TikTok a day don't even care what they watch any more.