Not the OP but for some reason this privacy-first messaging comes across as much more genuine from Apple than it does from Facebook or Google.

Probably due to the comparatively small number of privacy incidents, coupled with the business models of those companies compared to Apple.

Apple may not be perfect but at least it feels like they are trying.

Or perhaps it comes across as more genuine because they have better marketing while they follow the others as soon as it suits them to make a buck? They lied to their customers faces with building sized ads.

Follow the money.

Google and Facebook are built on renting our privacy out to the highest bidders. The minutiae of our lives are their raw materials, and to make more money they have to find new and exciting ways of exploiting our information.

Apple is built on making things we want to buy, then selling us stuff to do, watch, play, read or hear on those things. They’re also very good at telling us about those things and why we might want to buy them.

So yes, privacy-first messaging comes across as more genuine when it comes from companies that aren’t designed from the ground up to scrape every bit of information about us that they possibly can.

One can think Apple's decision was wrong while also thinking it wasn't intentionally malicious.

Five or more years ago, I gave FB & Google the benefit of the doubt—when the first few major privacy fiascos came to light, making it clear that it was a big deal and privacy needed to be cared about. Sadly, Facebook and Google have repeatedly shown themselves to be actively hostile to user privacy, and continue to double and triple down on invading privacy and breaching trust. They've been the giants who have proven the need for making privacy a primary concern of all tech hardware/software—because they are dependent on breaching and invading privacy to earn their income.

Apple does not depend on providing third parties access to identifiable data and profiles to better target ads, identify users, and destroy privacy and anonymity to earn their income. This pretty much means a wholly different default outlook from Facebook and Google. Apple continues to not just market, but take active steps toward increasing privacy and data protection for its users across its hardware lineup. I'm not at all suggesting Apple isn't worthy of criticism when they fuck up—they absolutely are. I'm only responding to the question of why a certain feature may not have been opt-in to begin with—when it appears obvious in retrospect that it should have been.

In short, Apple still has my reserved, cautious trust. Facebook and Google have long since lost it, and I can't even imagine what they might be able to do to ever earn it back.

When Apple starts building the privacy-related reputation that Google and Facebook have, I'll be all over the hate train. As it stands, as someone who believes he really cares about digital privacy for himself and others, I never thought about the fact that a Siri recording might be listened to by humans—but now, in retrospect, of course it was (I would have wanted to listen to recordings to grade my own software's responses), and of course it should have been opt-in to begin with.