Which side is behaving inappropriately? Hard to tell..
Both sides had legitimate grievances, and both sides did a poor job of trying to resolve them.
It also doesn't help if your attitude is that if you think everyone else is being an idiot you don't stop and check if maybe the problem is with yourself.
Anyone creating a fresh project right now with uglifyjs somewhere down the build chain will face this issue.
The only way to resolve this is by publishing a fresh, correct version to npm ragardless of what caused the issue.
The authors have failed to do this till now and the issue remains closed.