I don't understand why people have so much trouble with the idea of proto-feather on dinosaur.
Birds exist, therefore they must have ancestors with feather all the way until it let them fly.
Feather didn't instantly appear fully formed for flight.
Birds don't share most of their anatomy with their various dinosaur family.
We know for fact that huge birds that don't fly are possible, and we already know back in time the ecosystem allowed much bigger creatures.

No doubt if argentinosaurus species somehow existed along mankind, we would have made them extinct for petty reasons.