Re: To be fair...
"They also already have the ability to request call charge records to list all numbers to or from a nominated number."
Not going to help much for WhatsApp though is it? Hence the desire for carriers et al to hand over the WhatsApp equivalent of call records which I suggest is a) possible and b) reasonable so long as due process is followed. Not picking on WhatsApp, just using it as an example.
PS. Judging by yours and other comments, it's not just the other side that are fear mongering...