Translation:
SpaceX is moving on from having NASA as customer to having NASA as a competitor.
They have their own vision for human Mars exploration (it's practically Elon's manifesto), and SLS/Orion is not a part of it. They intend to make their point (to the politicians) by putting working hardware down on Mars before any of them, even after their competitors' protracted and expensive development cycle.
The use (or not)of the DSN will be very telling, because it is a political question and not a practical one. I don't expect NASA will want to cooperate. It will be very telling if we come to find that SpaceX is developing its own deep space communication capability.