"I want the government to have access to the data they legitimately need to defend me against terrorism. "
And what access would that be? They didn't defend anybody on 9/11, 7/7, at the Boston Marathon, at Glasgow Airport, they didn't stop Charlie Hebdo, they didn't protect Lee Rigby, they didn't stop the famed underpant bomber, they didn't stop shootings in Canada, they didn't stop the Madrid bombings etc etc. In the UK, off duty police officers and military personnel (including junior cadet forces) are advised not to wear uniform off duty because our government have evidently already ceded the streets to extremists.
So how exactly do you think that government will use your or my data to protect everybody from "terrorism"? They seem to think that terrorists send emails saying "Dear Abdul, hope you're well and family are good. Had good time on recent holiday to Syria, Mulla Omar sends his best. Please conduct suicide bomb and gun attack against Downing Street, on Jan 14th 2015, best regards, Abu Hamza."
I'd accept there's people they do want to track. But they already have all the powers they need by simply making the case to a magistrate. Instead they simply want to have access to everything on everybody because they are lazy and incompetent. The best way government can reduce the risk of terrorism here is to stop the endless dabbling in the politics, feuds and wars of Middle East sh*tholes, not by being able to read my email, and creating an archive in perpetuity of my grumble-browsing.