I don't think this is a transitive thing. Saying the Dracthyr Evokers carry the blessing of the Titans, or are Titan wrought, just because the Titans made the Dragons is like saying the Dragonsoul was in some way of the Titans because Neltharion had a hand in it. There's nothing to suggest the Titans were in any way aware of the creation of the Dracthyr, let alone had involvement, especially considering their creation would most likely have come about long after the Titans had left Azeroth in the hands of the Watchers and Keepers such as Tyr and the rest. In fact, it's stated that Neltharion took inspiration for the Dracthyr from ".....the scrappy mortal races of Azeroth", further distancing them from any direct Titan involvement, blessing or otherwise.