Hello Zech
Yes, this is true. Routing is simply the decision-making process of a router to decide to which next-hop router a particular packet should be sent (outgoing). Routing protocols allow routers to learn about routes that other routers around them “know” about, thus giving them more information to more successfully route packets.
But routing configuration and protocols on any particular router will only affect outgoing traffic from that router. Any incoming traffic is simply accepted and processed, and cannot be directly influenced. This is true of any routing protocol, including EIGRP.
Now having said that, it is possible to indirectly affect incoming traffic, by advertising various metrics to particular destinations to neighboring routers, but this is beyond your original question…
I hope this has been helpful!
Laz