So, nothing was stolen and if the story is true, the only infraction here would be that the Lerna copyright line was not included in the Rush license.
What part of my comment are you disagreeing with??
Copyright infringement is not theft.
The original BSD license did have a credit clause which led to considerable trouble and controversy, so they don't do that any more. IANAL, and this is extremely bad manners on someone's part, but no laws were broken.
That's the copyright notice. The license text is "this permission notice". So no, you can not leave the original author name off.
The BSD license differs in that it requires the resulting software to display the credits, not just the source code to contain it. (Which is why e.g. phones or cars have somewhere deep in the menus a point where they show license information, to fulfill the BSD requirement)