@onhwy61, I agree about a band sharing songwriting credits, even though it’s a rather Communist idea ;-). The Ramones did it, I’m sure there are others.
Levon Helm’s argument was that the instrumental parts he and the others created for The Band’s songs, and his and the other’s ideas for arrangements (listen to the out-takes of their albums to hear how the songs developed and changed in the studio) were just as much a part of the song as were the chords and melody. Levon’s drum parts are chock full of signature "hooks", parts without which the songs were incomplete.
I don’t begrudge Robertson being a business man; more power to him. What I do find objectionable is the way he deliberately mislead and manipulated both the other members of The Band and John Simon, producer of the first two Band albums. Robertson came to Simon and asked him to write charts for the horn section The Band wanted for The Last Waltz. Simon hadn’t received a royalty check from Capitol Records for years, and told Robbie he was not doing any more work for which he would receive no compensation. Robertson said he would look into the matter, and came back to John with an offer: if he agreed to forfeit all future royalties from the sale of the two Band albums he produced, Capitol would pay all past royalties due him. Simon balked at that idea, but Robbie, according to John, told him that he would make a lot more money from The Last Waltz album and movie than he would from future sales of the first two Band albums. John said okay.
What John and the other members of The Band didn’t know was that Robbie was signing agreements with the company that was financing the movie, agreements making Robbie an executive producer of movie. All the producers made money off the top of the movie’s grosses, The Band members and John Simon off the net. After all production costs, advertising, etc., there was very little left. Robertson ended up making a small fortune off the movie, John Simon and The Band a pittance. Robbie KNEW that would be the case, and knowingly tricked, manipulated, John Simon into signing away his future royalties for what he, Robertson, knew would be very little. All to make himself as much money as possible, at the cost of Simon and The Band. When Robbie said "I did what I had to do", he is admitting as much.