jings, if you really don't understand what the proposal is about, why are you getting hot under the collar about it? You could be misinterpreting things.
As for disestablishment of the C of E, well, I think that will happen sooner or later anyhow, possiblt bit by bit, possibly not, but whether this change, should it happen, has much to do with that is arguable.
But the idea about the change in the marriage law makes perfect sense to me, and apparently to plenty of others. mice has already explained it clearly, though I thought the article quite clear too.