I find the background part in this question doesn't give useful information, or at least the answers don't use it. Should I delete the whole part to make the question short and to the point?
In you specific example, I agree with removing the background.
However, in general, I would be very careful to remove background information, because academia varies more than you think it does: What you consider irrelevant from your experience may be relevant in other fields, countries and similar. Moreover, we encourage new users to rather give us too much background than to little, as they often even know less what’s relevant. It might thus be discouraging if we remove the background early on.
As an alternative to deleting consider moving the background under some subsection such that the relevant parts of the question are streamlined and the background isn’t lost.
I see no issue with removing that section, personally. I agree that it doesn't add anything substantiative to the question.