NASA does not build a damned thing. ULA (Lockheed Martin, Boeing) builds the EELV rockets. SLS is being build by ATK while Orion is built by Lockheed Martin.
This is just ULA being afraid they will lose their iron rice bowl.
NASA engineers are intimately involved with the development, procurement, and more important.... the R&D that is going into the the development of the SLS.
The EELV is a total red herring to your argument because the EELV program is something the Air Force, not NASA, created. NASA doesn't have anything to do with EELV rockets except to use them on occasions for flying payloads into space.... payloads that were originally supposed to be launched by the Space Shuttle but couldn't because it was thought that launching these payloads wasn't worth risking a crew (and a roughly 2% chance per flight of total loss of crew).
It is also a huge oversimplification that SLS is being built by ATK. Yes, ATK is a major contractor for the SLS, but literally hundreds of other contractors are involved too. But that doesn't even scratch the surface of this lie you have said by saying "NASA doesn't build a damn thing".
The most important thing to note is that NASA, through Congressional appropriations, is paying for the development of SLS. That is not true for the Falcon 9. While some NASA funds have been used for getting the commercial transport services contract going as well as the commercial crew program, that is a fixed price seed money contract where SpaceX is required to provide the bulk of the funding. More importantly, if there are any cost overruns, delays, or other problems... especially of a financial nature... SpaceX is required to take care of the difference from its own investors and cash reserves. If the SLS gets delayed by another decade and costs another $10 billion, that will be entirely paid for by taxpayers, not ULA, ATK, Aerojet, or any other contractor.
I think that difference is important, and something that is totally missed by your comment.