Unfortunately, the license allows this. It’s also a social issue - why shouldn’t a faster mover be able to slop a feature faster than the project owners? Who cares if it’s disruptive to them?
I’ve seen this happen on other projects and beyond rejecting the changes, I’m not sure what to do. It’s damaging morale when someone has worked weeks or months on a feature, worked with countless individuals on planning and implementation, and then someone releases a vibe coded slop fork with the last 5-10% and then takes credit as if they’re some genius doing something useful or helpful.
Ultimately the issue is manners, but when there is opportunity and generosity, the generous are going to be taken advantage of.