Because it's going to be a great deal for a few conglomerates and a shitty deal for everybody else!
It's also going to give the control freaks in the US an absolute monopoly over policing the internet. You will access the world wide web at their pleasure, and if you're not pleasing them, you'll be out of luck.
The secretive nature of these negotiations gives the impression that what's really going on is a not-so-secret attempt to cobble together an anti-China coalition.
That will not further trade, nor will it further peace.
This is the last gasp of a spent hegemon.