

When you are seeding, you broadcast to other peers that you have pieces available. The most efficient way to exchange data is for them to open a connection to you. Without an open port (from port forwarding) they have no way to make this direct connection.
Whether you like it or not, that’s more or less what happens. You can/will lose a bunch of accounts for causing trouble. Sometimes I think it’s a bit over the top. Instead of keeping out toxic or non-contributing folks it becomes a personal vendetta or innocent violation.
Overall, I’m a fan of banning known bad users, but restraint should be used and collected personal information should be minimized.