Typical "science" for hire. Materials supplied by Mars inc. Flavonols in question largely killed by "Dutch process" used to make chocolate. And how much Cocoa is in cheap chocolate anyway?
Lots of non-dutched cocoa products are out there. However, after a brief look into the subject after reading this article I read that a lot of the beneficial compounds are removed in commercial chocolate products because they are associated with bitter flavors.
And agree that the study should not be considered without looking where the money came from, but at least they explicitly noted it was funded by Mars.