Because of course, 42.2% sounds scarier than 15%, 27.2%, 32%, and 35%.
I don't think the magnitude changes the argument. While you may have a problem with his math overinflating the problem - if you acknowledge the problem exists, then you should get to the next point of the argument.
I think you're saying that a double taxation starting from a 15% capital gains tax may end up being less than a single tax at regular income - assuming your regular income puts you in a >30% tax bracket.
So why don't you just say that to Elmer instead of the stupid tit for tat?
By the way, Elmer has already stated that he would support sharing the tax burden between the shareholder and the corporation, so I don't know what's left to argue.