One of the key ideas is that each user chooses what repositories they host via pretty fine-grained policies. This means you can easily block content you're not interested in seeding, or simply configure your node to only host content you explicitly allow.

You can also choose which public nodes to connect to if you'd rather not connect to random nodes on the network; though I don't expect most users to go this route, as you are more likely to miss content you're interested in.

Though Git (and thus Radicle) can replicate arbitrary content, it's not particularly good with large binary files (movies, albums etc.), so I expect that type of content to still be shared on BitTorrent, even if Radicle were to be popular.