That's the thing. Nobody who doesn't owe the Saudi Royal Family huge favors, is going to argue against protecting innocent people from terrorists. And it's exceptionally rare to find anyone who would say child molesters should be anywhere but in a cage. And crack dealers. And actors in bad movies.
The only real argument against most of these classes of people being spied on, is two fold. First, to spy on the bad people, you have to spy on the good people, and narrow your list down. Second, it's going to reach the point where good people can't protect their privacy from idiots on the internet by, say, encrypting their email before sending it.