with the additional requirement that a carrier could not evade warrants or other authorized orders by encrypting the communications or hiring someone else to do so.
I think the point here is that warrants aren't mentioned. The carrier is expected to roll over & drop its pants whenever the "authorities" ask. If it needed a warrant signed by a judge first there would be less opposition.
Doesn't make it any less pointless, of course. Just hook up your RPi "Enigma" machine to your email program, and you don't need ISP encryption at all.