Hrm, I don't really like this.
First of all, it is not correct. I agree with most of what Robert Harvey says here. We define topicality very specifically. You cannot ask just any question about programming on Stack Overflow. Our requirements are much more nuanced than that, and we lay out those specificities in the help center.
So the "or" phrasing that you're proposing is wrong. The second part of the phrase is required to modify (i.e. define) the first part: your question is off-topic because it is not about programming in the way(s) that we require it to be. The dependent clause explains the independent one.
Which is all great, but this is where I start to disagree with Robert. He says that
"Over time, I began getting into the habit of calling a question 'off-topic' when it didn't meet the scope requirements of the site."
This makes sense, and all of us regulars have done the same thing. Over time, I would argue, we've grown to accept things as intuitive that are not. We associate a lot of baggage with the "off topic" label, baggage that new users cannot reasonably be expected to be carrying.
Like all jargon, it works great as shorthand between experienced users when we're having Meta discussions. But as I've argued before, this nuanced and highly-specific way that we use "off topic" runs counter to common usage. In common usage, when someone says that something is "off topic", it means it has nothing to do with the topic. That much is obvious, I hope. But then the question is, what is the topic of Stack Overflow? Do we honestly think that anyone who does not hang out regularly on the Meta site is going to say "oh, this list of 12 things in the help center"? No. We don't even say that, unless we're called on the carpet to justify one of our decisions. The site itself is very clear about being about programming, so anyone who honestly answers the question "what is the topic of Stack Overflow?" is going to say "programming". And therein lies the rub. There are at least two close reasons nestled under "off topic" that can only be used with questions that are clearly about programming.
So I would also oppose this change on principle because it fails to fix any of the root problems here. At best, it'll just make us think we're doing something to address it when we're really not.
This message is not the confusing part to people. It is the name of the major category, "off topic". If people read this more descriptive text carefully, it is possible that they will come to understand that we mean a very specific thing by "off topic". That thing that Robert, and I, and the other regulars have just internalized, even though it runs counter to common usage. When you tell someone that their question is "off topic" on Stack Overflow, they think about the fundamental topic of Stack Overflow, which is programming. Educating the user about the finer points of how we define topicality would be nice, but it isn't realistic. The users who understand this are not asking these questions and having them closed in the first place.
If we're going to slap a label on the question, it needs to be the right label. That means it needs to be patently obvious to regular people. "Off topic" is not the correct summary of all the closure reasons that fall under that category. And adding some equivocation to the detailed message is not going to solve that fundamental problem.
Stack Overflow is a site for experts on programming. It should not be a site for experts on Stack Overflow. We already have a site for that, and if you're reading this, you've already found it. It is our job to make Stack Overflow the best programming site that we can. If the close reasons are unclear, ambiguous, or subject to honest misinterpretation, which I argue that they currently are, then we have not done a good job. For lack of a better phrase, we've created a leaky abstraction.
I may have said it flippantly here, but I meant it. If we really don't care about making the close process (and specifically the reasons) clearer and more understandable to normal people, then let's get the "not a real question" back. It worked just as well as "off topic" does: your question is not a real question for Stack Overflow, given how we define questions. I will admit to thinking that the hand-wringing about changing close to "on hold was silly. But it seems everyone now thinks that was a positive change. Why? Clarity. We experts all knew what "closed" meant, we knew that it implied an ability to re-open. We knew it meant a temporary "on hold" status. But new users didn't, and those were the people whose questions were getting closed. The way we were using "closed" was inconsistent with common usage. If we're serious about revamping the close system for clarity, we can't just go halfway and declare good enough.
Words have power. And if you disagree, you're a stupid-head.