Just to be clear, the dark pattern isn't the re-authentication itself, it's hiding the "Subscriptions" button behind a button that says "View Apple ID" where many people (myself included) may not think to look. The re-authentication just compounds the problem by hindering discoverability of where the "Subscriptions" button actually is, because you have to go through a password prompt to find it.
The Settings app built-in search doesn't work either. If you search for "Subscriptions" it doesn't appear, because it's behind hidden behind this password prompt (to be more generous, that entire screen is probably only generated once you've logged in, but it doesn't have to be that way).
Additionally, the "View Apple ID" button itself is also non-obvious: you have to click your email address first for it to come up as a pop-over. I recognise my email address in blue is a link to my account information, but a less experienced user might (reasonably) think otherwise. It would probably be better for your account name to have a right disclosure arrow next to it (taking you to a new view with your account options inside) to specifically indicate that touching it takes you to this new screen, because that's the way everything else in the Settings app works.
To solve all of this, you could just as easily put the "Subscriptions" button one level up in the "iTunes & App Store" screen, before the password prompt, and only prompt for a password after the user has clicked it. This would solve all of these problems.
If this sounds confusing, that's because it is. That's the real problem here.
There is intended to be a difference between poor UX and the godawful phrase "dark patterns." The amount of overintellectualization you can do about a given experience doesn't contribute to the darkness.
This, of course, is part of why it's such an awful phrase. It's too nerd-cool to avoid being overapplied by cool nerds.
The Settings app built-in search doesn't work either. If you search for "Subscriptions" it doesn't appear, because it's behind hidden behind this password prompt (to be more generous, that entire screen is probably only generated once you've logged in, but it doesn't have to be that way).
Additionally, the "View Apple ID" button itself is also non-obvious: you have to click your email address first for it to come up as a pop-over. I recognise my email address in blue is a link to my account information, but a less experienced user might (reasonably) think otherwise. It would probably be better for your account name to have a right disclosure arrow next to it (taking you to a new view with your account options inside) to specifically indicate that touching it takes you to this new screen, because that's the way everything else in the Settings app works.
To solve all of this, you could just as easily put the "Subscriptions" button one level up in the "iTunes & App Store" screen, before the password prompt, and only prompt for a password after the user has clicked it. This would solve all of these problems.
If this sounds confusing, that's because it is. That's the real problem here.