There is really no excuse for having one's addon obfuscated. In fact, Tampermonkey is the only addon I know of that deliberately obfuscates its code! That brings the question: what are the developers trying to hide and why?
If you don't want anybody else to fork your extension, just release it under a restrictive custom license, and everybody will be happy. There is no way somebody could abuse such a license and benefit from it. So we'll be looking forward to a release w/o deliberate obfuscation!