IMO Authenticity with Shanties is only achieved, if they are sung in a nmanner that they can be worked to, what prompted MacColl to perform stormalong surely is not as important as whether you can work to the shanty, it does sound like it is influenced by Hugill.
However people will sing them how they like Regardless of scholars, and it could be argued by some that a pleasant musical experience is preferable to an out of tune rendition that can be worked to.