afaik that torrenting via tor hurts the tor network. Tor works by routing your traffic to three different hops, the last hop being the exit node, optionally a bridge hop if tor is censored in your country, and encrypting it along the way. Since tor is run by volunteers, they have to opt in by becoming a middle/guard relay or, if they have the ability to fight legal notices, an exit node. Torrenting through this network increases the bandwidth requirements of the networks and makes everything slower
I2p works by having everyone be a router which passes information to other routers, so by default if a malicious node gets a packet from another node, the malicious node is not sure whether it originated from it or if it was merely another hop. The upside is, since everyone is participating as a router, torrenting actually helps the network because more nodes will see you and it advertises that “hey, this guy right here is a router” and some packets will be sent to you for you to route.
Although i2p is supposed to be a “network within a network”, some i2p nodes volunteer to be outproxies and will route traffic to the clearnet. These outproxies face the same legal liablities as exit nodes in tor. So it is indeed possible to torrent through the clearnet, provided you use an outproxy routing your traffic to i2p