When the Olive Branch Petition arrived in England, its contents hardly even mattered.
There were elements of Parliament who were strongly disposed toward punishing the Colonies, and punishing them hard. The folks who were still pro-American were dwindling in number, because of the way it could affect their political futures.
In short, the King had decided what he thought, and how he was going to handle it, and everyone else either bowed to it or faced losing their position. And it didn’t matter that he was a little bit crazy; he was the King and what he says, goes.
Presumably we’ve learned the lesson behind that kind of thinking.