Background information helps establish the context in which the question is asked. In many cases this can be a good thing. In no case that I can think of can we say that removing that information preserves the intent of the original poster.
That said, there are other things one can do to make the question easier to read. I originally posted these as a comment on bilbo_pingouin's answer, but I think they deserve to be in an answer instead.
- Edit the question and
**boldface**
the important part to make it stand out better. This works well if the important part is a few sentences or less.
- Edit the question and put a
# heading
above the important part. This works well if the important part is longer, but well isolated.
- Edit the question, copy the specific question to the top, and prefix the remainder with something like "background material:" to make it clear what is extra material that can be useful to understand the question but might not be required reading. This works well if the specific question is fairly well-contained.
- Edit the question and give it a solid title. This helps readers quickly get an idea of what the question is about, which aids in skimming for relevant details. While witty titles can be fun, they are not always conducive to promoting a quick understanding of what the question is about. Just a really good question title can be what makes the difference between a moderately bad question, and a fairly decent question.
All of these preserve the intent of the original poster, while improving readability or answerability. Which is much better than to edit out large portions of what the original poster wrote which, after all, are relevant to the question.
It is a very different matter if the excess material is unrelated to the question that is being asked. As a slightly contrived example, which obviously would need to be much more detailed to be an actual acceptable question, if someone were to post:
I love chocolate and strawberry ice cream, which I eat while building my worlds. My unicorns descended from horses but evolved naturally a horn projecting from its forehead. How did this horn evolve?
then even if the non-question part is fairly long, it would be perfectly reasonable to edit out the first part:
I love chocolate and strawberry ice cream, which I eat while building my worlds. My unicorns descended from horses but evolved naturally a horn projecting from its forehead. How did this horn evolve?
leaving only the part of the question that is actually relevant to answering the question:
My unicorns descended from horses but evolved naturally a horn projecting from its forehead. How did this horn evolve?