They think they are Google - you know, the guys that made the Internet searchable. I'm pretty sure they know what they are doing.
Call verification is used by many services to establish ownership of an account, and to provide a fallback mechanism that automates the recovery of an account. Google likes to automate the shit out of things. This is no different.
I hear that you are angry about their policies, but I really don't hear why you are angry other than it's 'intrusive'. Are you afraid they are going to do something horrible with your phone number but not your searches? Do you have similar concern and passion for what the NSA has done? Are they related to each other?