You were not lied to. You misunderstood how KS works, and possibly what a physical DRM on a disc means.
Do a little search for the word "Physical" on the KS page and look at what you find.
Like many other kickstarts, the ED one tagged with the word "physical" any rewards that would require real world delivery. Which is why you will see among the optional rewards things like "physical CD", "physical paperback copy", "physical hardback copy", and "physical 3D model". Thus, a "Physical DRM-free boxed edition" means a real world boxed edition that is DRM-free, rather than a boxed edition that does not have a physical DRM.
Besides, trying to use the meanings the way you point in order to weasel out of the promise of being DRM-free is the kind of behavior that easily makes me stop dealing with a company. And in some places of the world it alone might be considered fraud if intentional.
BTW, if you think about lies of omission, then those backers that trusted the promise of an offline mode were lied to anyway. While Frontier promised an offline mode, they only intended to deliver it if they could create it without sacrificing their artistic vision for the connected game. But they never explained that last part.
It might have been unintentional, of course, but how they dealt with it going forward, letting it simmer hidden until it all exploded last week, was certainly an error.