I found I2P much better than Tor network, and now it supports BitTorrent protocol too https://geti2p.net/en/docs/applications/bittorrent .
Why haven’t the pirates migrated to I2P? Why are we still using clearnet and making people backout of seeding cause of DMCA?
I’m not saying you’re wrong because I don’t know the i2p details, but it sounds like you may be mixing up being connectable with seeding vs leeching.
Once a connection is established, data can go in any direction, seeding (uploading) or downloading. Getting a connection between two peers in the first place needs one party to be connectable via an ip:port. That is already a problem with a massive number of clients behind NATed VPNs