"Everyone one in the government, except one lone temp, is a coward and a poltroon."

It's not just everyone in the government, it's everyone in EVERY GOVERNMENT on the planet. How realistic it that, when there has not been one other moment in history when all governments on earth acted together in concert? Not one leader anywhere said, "No, I'm not going to hand over my country's children to intergalactic junkies just because the British government told me to." Last I looked, governments were made up of politicians who would be more than eager to throw each other under the bus if would make themselves look good.

Which brings up my next point: I can't imagine a government or politician anywhere that would willingly kill mankind's best hope of defeating an alien threat just to cover up the actions committed by the administration that was in power 45 years before. They'd be throwing the members of that administration under the aforementioned bus. No, their first concern would be to employ the best available means to fight the aliens (Jack Harkness and Torchwood), not "Let's destroy our only chance to win."

In order for CoE to work, the audience has to accept the fact that every major character behaves with a stupidity that defies belief and, in the case of Torchwood, totally out of character. It's an acceptance I'm unwilling to give.