So I asked a question pertaining to iOS 7 and was massively downvoted. I assumed it would be ok as there is an ios7 tag, but people downvoted it because of the NDA, even though I didn't mention anything new. Curious, I looked at the ios7 tag and found that all of the questions there were similar: no breaking of the NDA, but massively downvoted for that reason. If any question with the ios7 tag is going to be downvoted, why does it exist in the first place, and can it be deleted?
Technically, the tag exists because someone with 1500 reputation created it and applied it to a new question (privilege description here). More than one question has been tagged with it, so it will most likely persist.
A tag existing on the site is not an endorsement of everything about that topic, so it can't be used as a metric to determine what is or is not on topic. In this case, programming questions involving developing for iOS 7 are on topic. Others are not, such as how to downgrade the OS on your iPhone after installing iOS 7, or questions about selling UDID slots to non-developers (yes, people were asking that).
That said, I think people are being a little too harsh when it comes to questions about prerelease OS versions like this. There seems to be a bit of a vigilante effect at work here, where people feel that they need to punish anyone attempting to break their NDA with Apple. I'm bound by the same NDA, but that only covers things that I disclose. I am not responsible for policing anything else that others may leak, nor is Stack Exchange. People need to stop flagging these things, because I'll keep declining them.
In general, my take has been that if someone is asking a question about a bug that is specific to a particular build of a beta OS, that's too localized for Stack Overflow. That may not apply with the new closing reasons coming down the pipe, but I don't see how questions which deal with something that may be fixed next week will help future visitors. If it's a bug you're dealing with, it does no good to report it here, and you should instead use Apple's bug reporter.
However, broader questions about the usage of a particular new API are viable here, and it's not up to us to close them. It's unfortunate that a good question like this asked now may be downvoted into oblivion, where the exact same question asked in a few months might get great answers and be highly upvoted.
At the worst, I would leave comments on these directing people to Apple's developer forums, which is where you can discuss these matters freely and where you'll actually get the engineers behind the technologies to respond directly. You can also help shape the direction of the OS that way.
As an aside, I'm not a huge fan of OS-version-specific tags, because people often use those and forget to apply the more generic [ios] to them as well. This significantly reduces the visibility of these questions, and whatever issue they're working with in iOS 7 may still be the case in iOS 8, etc., so you want people in the future to find this. That's a side issue, though.