Bethesda was under no obligation to talk to these mod devs beforehand. But it sure makes them look bad. As a recent comparable, Concerned Ape was open and communicative with all the mod devs before releasing his latest patch for Stardew Valley, a game that is just about as old as Fallout 4.
Bethesda has become a literal laughingstock at this point in time and it's just funny to point at them every time they rack up another L.