Well, the way I see it, there’s a few possibilities, with different parties to blame.

Mechanical error would be the fault of Delta/Endeavor. This is a tested plane with many many flight hours. A mechanical issue could only be a maintenance error. But so far there have been no confirmed reports to suggest this.

Pilot error would be the fault of Endeavor’s training.

It could possibly be some freak gust of wind right at the worst moment. Second-to-second weather can be hard to deal with, especially at 40 km/h.

Or if ATC failed to adequately convey the conditions, that would be the fault of the GTA airport authority, but that doesn’t seem to be the case.

TL;DR with the evidence we have so far, we’re looking at pilot error, or weather that was just wrong place wrong time.