That's fair, you certainly can use rabbitmq in a distributed and decentralized fashion.
You bring up an important point though... What is important is the topology we're promoting and the platform we've built to support it. The actual queue is less important and it made sense for us to own that piece to achieve our goals.
So, why not just deliver that topology using off the shelf components? Rabbit, Kafka, ZeroMQ, ... the toolbox is deep. This is not meant as a criticism, I am simply trying to understand what I am missing when I look at your design :-)
