Right for the wrong reasons?
Ok, no one trusts Oracle to be anything other than the greedy, arrogant, morally unhygienic company it's always been. No one expects it to suddenly—or even, ever—offer top-class, good value products or services that in any way resemble their marketurds' onslaught of hype. The Oracle dodo was already disappearing over the horizon 20 years ago when the company Christmas tree (the RDBMS that was, once, valuably distinguished) became invisible under the unholy spawn of too many acquisition orgies—the festoon of shiny baubles of (badly-) "integrated suite" shyte.
So no one believes that Oracle's motivation for this legal complaint is anything except self-serving.
But that doesn't mean they're wrong about the principle of the thing. DoD's excuses for single-sourcing (and doing it conspicuously badly, if you look close) are even leakier than a littoral combat ship:
"[DoD] ... justified its decision by saying that running a multiple-award contract would slow down the bidding process, increase project costs, and complicate management. ... Pentagon has argued it will avoid lock-in through built-in exit points and various contractural [sic] requirements on portability and price"
—which translates as "DoD is (i) incompetent to manage a major competitive tendering process, (ii) doesn't realise the phenomenal financial and delivery risks of lock-in, (iii) has either failed to conduct or has dismissed the results of a SWOT analysis of this initiative".
Now, an ironic perspective on this might acknowledge that DoD has had an entire century of procurement mismanagement experience—with the F-35 fiasco only the latest reminder of its heroic institutional incompetence. This is an organisation, after all, that knew exactly what had gone wrong, how, and why, with the F-111 program fifty years ago, and then went ahead and made all the same mistakes again. So the DoD statement is bizarrely truthful per pt (i) above ... though probably unintentionally so.
Pts (ii) and (iii), though, ought to have rung alarm bells right round the E ring, because whatever costly dependencies the Pentagon may tolerate with its hardware (or, to be fair, are inflicted upon it through corrupt pork-barrel congressional greed), this is major information technology we are talking about. Russia and China may be celebrating the stupidity of F-35, but they cannot do any more than Lockheed, Congress and the Pentagon have already done to turn that particular project into a military Achilles heel: they can't subvert the plane while in flight and make it crash, or turn right round and shoot up its mother ship. At best they can just hope for chips of runway concrete chipping the stealth paint for a 36-hour trip to the skincare salon.
IT is another matter entirely. The foes mentioned above are bad enough*¹, but there's also an almost limitless number of smaller nation-states with the intent, the potential and eventually the capability to inflict strategic-level damage on US military IT*². Why on earth would you make their job even easier by single-sourcing? Bear in mind, wars can be lost for a lack of shoes as much as missiles: claiming that your precious data is "only" logistics, HR, supposedly unglamorous or even trivial support stuff is actually the same as saying "If it busts, we lose".
Of course DoD should be looking for multiple suppliers, and Oracle's stated reasons are sound enough, but the far more crucial one is national security. Inevitably, the Pentagon will come to depend more and more upon its suppliers—sucking in the unwary, holding them and their data hostage and then lovingly fleecing them is what every major cloud provider ultimately aims for, after all—and the idea that it will depend upon just one is ... unbelievable.
*¹ One of them appears to be trying out the unique military strategy of overwhelming a nation's defences via BlitzTweet.
*² Not to mention the Orange Idiot's "400lb guy sitting on a bed"*³.
*³ No, not the one mouthbreathing around three Big Macs while gaping at Fox&Friends. That's Vlad the Emailer's BlitzTweeterBot. Do try to keep up, guys ....