I think they are trying to decide what the capital gain tax and dividend tax rates should be for non-retirement accounts. This isn't (yet) a plan to tax Roth accounts or to tax non-Roth accounts at anything other than normal income tax rates. They want to be able to raise cap gains and dividend rates on everyone, but still be able to weasel out of Obama's campaign promises of not one tax increase on those making under $250,000.
They might make out better than doing gains or losses or ADD the fee thing.
I'm sure they don't like it when folks claim a loss..