Very odd association there, but perhaps some factors come into play. For one, my friend is Evangelical, and two, I'm Catholic with a short history with Opus Dei. I'd have thought, however, that the major problem with DVC was how the fiction says "rubbish" about our Christ. Everything said about the Opus Dei and the Priory of Sion, false as they come, are insignificant in comparison.
I dug a bit deeper and her reaction appears to be based on some unnamed (she didn't say) source on the Internet. That's the way information works on the Internet: truth is assumed to be in the voice of the loudest (with the most number of hits, perhaps the best format, the most clever prose).
Eh, no. Quid est veritas? What is truth? Truth is objective and verifiable. It is supported by facts and is the basis for fact. Truth is a reference as well as a foundation. it stands regardless of popularity or age.