I am referring to this edit.
The OP is almost entirely erasing the content, and changed the first title to a completely new question. (At least it seems to me.)
I think the mod tried to salvage the question, but isn't this a too much intervention?
The question "Are all these lyrics OK?" is off-topic because it's proof-reading. Focusing the question on the specific on-topic question "Should 'Though today I have to live' be 'Though today I have to leave'?" so that the question could stay open was a reasonable thing to do. That question was in the original, so while the scope of the question was reduced, I don't see that as creating a new question.
The author is always free to revert the changes or clarify their question.
What is wrong with salvaging a question? Yes, we should not make edits that change the spirit of the question, especially ones that invalidate answers. But improving questions has always been welcome here.
For context, OP provided the entire lyrics to a four minute long song from a seemingly reputable source and asked if they were "OK". Then OP specifically mentioned one word, live, in one line
Though today I have to live
OP thought they heard leave. I narrowed the question down to this specific concern. Now, you could debate whether or not the new version of the question is on-topic. But I think everyone can agree: the original was too broad and a request for "proofreading". That's clearly off-topic.
As Colleen mentioned, we would much rather have something that's arguably on topic than something that's clearly not. When it comes to edits, I think everyone agrees that edits should not change the nature or spirit of the question. We should not make big assumptions, or large leaps of logic, to improve the question. We should not put words in OP's mouth. And I don't think I did that here, as OP's specific concern was explicitly mentioned in the post. This edit itself was a bit unusual in that it was a rather large subtraction rather than the usual significant addition. Yes, I literally changed the title to a new one, and the question is superficially different. But I did not make any big assumptions about OP's specific interest. I simply trimmed the excess, off-topic context to focus on a specific concern.
Attempts to salvage questions are not uncommon. These kinds of edits come from all kinds of users, mods and non-mods alike. The edits themselves can range from making minor formatting changes to clarify a problem, to including more context from a source material. Again, this particular case is a bit unusual. But in general, reasonable edits that preserve the spirit of the question should be welcomed and encouraged.
And of course, if you're not sure, you can ask OP directly!
The question was off-topic according to the rules mentioned in the help center. The OP had written "I'm not sure if the lyrics are OK" in the body, and "Are the lyrics OK?" in the question/title. What is "OK"? What is the definition of "OK"? OP had not clearly identified what they mean by that.
The original question would require one to go through each and every line to see if they were all "OK" - which is proofreading and hence off-topic. A specific source of concern was not clearly mentioned.
Please don’t ask any questions about the following topics. They are out of scope for this site:
- Proofreading (for example, "Are there any mistakes?" or "Is this correct?"), unless a source of concern is clearly specified
The edit by the moderator shaped the vague question into a specific one. Had the moderator not done so, the question would have been flagged as off-topic by now.
You wrote "The OP is almost entirely erasing the content..." - I am guessing you are referring to the moderator cutting out the lines of the lyrics. The original source/link to the lyrics was posted and so there really was no need for the whole thing to be there. Cutting the lyrics short makes it easier to skim the whole post, and users are able to get to the main question more easily.
To answer your question: "... but isn't this a too much intervention?"
To me, no, it is not. The degree or level of intervention is just right.