Dread Lord first compared to DK first

How is DL first not the general meta? No matter how i theorycraft, i cant see how DK first is a better option.

DL fast expands.
Creeps easier.
Lvl3 Carrion Harass, and T2 pivot into DK+Ghouls creeping is S tier.
Carrion Swarm is super good.
Did they play DH or BloodMage? Who cares, just range and sleep spam, or bring a Zepplin along with you since you have excess resources.

I really dont understand the science of how the meta is DK first. DL can play against basically everything, and a T2 DK doesnt really impede DK progress all that much.