Partially, it’s accurate when using the BT protocol. However if you use μTP (Micro Transport Protocol), it has “support for NAT traversal using UDP hole punching between two port-restricted peers where a third unrestricted peer acts as a STUN server.”
When you are not port forwarding you can only download from users who are actually port forwarding, or am I incorrect?
Partially, it’s accurate when using the BT protocol. However if you use μTP (Micro Transport Protocol), it has “support for NAT traversal using UDP hole punching between two port-restricted peers where a third unrestricted peer acts as a STUN server.”
https://en.wikipedia.org/wiki/Micro_Transport_Protocol