Bel.Air

The difference here is presumably scale. The sheer scale of Apple's product base means any new service rollout basically instantly creates (or crushes) a market or niche, in this case millions of users could potentially go "dark" after an iOS update. 
What I understand from their argument is if you feel the need for protection there are pretty good tools out there and you're free to use them, but it's unreasonable to make it the (almost) default option for anyone as this could quickly lead to having rule of law undermined by bad actors (yes I know it sounds like the FBI San Bernardino argument, because it kind of is really).

ISPs have a legal obligation to record specific data and hand it over to law enforcement if requested to do so. Privacy is all fun and games until shit hits the fan, and you're not able to investigate basic crimes because everyone is able to fly under the radar by the flick of a setting.. all because libertarian ideas are overly represented in tech. I'd argue the whole privacy argument out of California isn't doing much in the way of freedom of speech or protecting human rights in many places around the world, and not even that good at protecting people from super precise and intrusive ad targeting (because most people want and accept it anyway).