You are supposed to get consent by showing both options equally. Note also the wording of "not now". That is the kind of option that feels like the app is going to bother you about it again. Moreover, it communicates inevitability. You can opt out for now.

All of this is clearly made to get people to opt-in. Heck, it is not even clear that the "not now" option is clickable.

If you click "not now" it pops up again later.

At least it used to, and it was really abrasive about it. Definitely dark pattern behaviour

Consent can be tricky when you create a path of higher and lower resistance. This is especially so for people who try to avoid conflict (teenage girls here especially). They may give consent simply because it's what is expected of them, and rather than what they actually want. UI design for such consent forms has to be carefully considered so as to make it 'socially acceptable' to decline.

That specific popup is a clear example of how to maximize acceptance in a big portion of the population. I can almost guarantee you that popup design was chosen based off A-B testing, and had the highest rate of acceptance among designs.

Yes - Call and Text history are not required to make this feature work - only your contact list (which is all iOS sends). They bundled this extra invasive data collection into the consent request. And we are used to apps requesting access to contacts to find people you know on the platform, so syncing your contact list is expected for this feature. What's not so expected is also sharing your call and text history, which is conveniently mentioned in a low contrast text blurb. That's the dark pattern.

In a world where we have already been preconditioned to certain design patterns, the blue button is clearly the more prominent and will subconsciously be considered the "default" option.