I am confused if this is a battle of mesh and routing protocol why is 802.15.4 with rpl left out
It's not intentionally left out. Battlemesh is driven by the people who come there and participate, and if nobody is interested in a particular protocol or approach, it will not be set up or presented.
Disclaimer: I'll be presenting cjdns [1], the encrypted IPv6 implementation using public-key cryptography for address allocation and a distributed hash table for routing.
That's a shame, I wish I had known about this before I might have been able to put something together and present. The start-up I work with is heavily invested in developing mesh networking devices.